Methods of providing solriamfetol therapy to subjects with impaired renal function

ABSTRACT

The invention relates to methods for decreasing adverse effects associated with solriamfetol ([R]-2-amino-3-phenylpropylcarbamate) therapy in subjects with impaired renal function. In particular, the invention provides an optimized dose escalation scheme for subjects with moderate renal impairment which results in the subjects having increased tolerance to adverse effects associated with the administration of solriamfetol. The invention also provides adjusted dosing for safe therapeutic use of solriamfetol in subjects having severe renal impairment.

FIELD OF THE INVENTION

The invention relates to methods for decreasing adverse effectsassociated with solriamfetol ([R]-2-amino-3-phenylpropylcarbamate)therapy in subjects with impaired renal function. In particular, theinvention provides an optimized dose escalation scheme for subjects withmoderate renal impairment which results in the subjects having increasedtolerance to adverse effects associated with the administration ofsolriamfetol. The invention also provides adjusted dosing for safetherapeutic use of solriamfetol in subjects having severe renalimpairment.

BACKGROUND OF THE INVENTION

APC and its phenylalanine analogs have demonstrated application in thetreatment of a variety of disorders, including excessive daytimesleepiness, cataplexy, narcolepsy, fatigue, depression, bipolardisorder, fibromyalgia, attention deficit/hyperactivity disorder andothers. See, for example, U.S. Pat. Nos. 8,232,315; 8,440,715;8,552,060; 8,623,913; 8,729,120; 8,741,950; 8,895,609; 8,927,602;9,226,910; 9,359,290; and 9,610,274 and U.S. Publication No.2015/0018414. The structure of the free base of APC is given below asFormula I.

Those of skill in the art will appreciate that methods for producing APC(which also has other names) and related compounds can be found in U.S.Pat. Nos. 5,955,499; 5,705,640; 6,140,532 and 5,756,817.

[R]-2-amino-3-phenylpropylcarbamate hydrochloride (APC-HCl) is aselective dopamine and norepinephrine reuptake inhibitor. At micromolarconcentrations, APC-HCl can selectively bind and inhibit reuptake atdopamine and norepinephrine transporters without promoting monoaminerelease (See, Carter L, Baladi M, Black J, JZP-110: adopamine-norepinephrine reuptake inhibitor (DNRI) with robustwake-promoting effects and low abuse potential. Poster presented at:Winter Conference on Brain Research; Jan. 23-28, 2016; Breckenridge,Colo. Poster #Su23, 2016; and Baladi M G, Forster M J, Gatch M B, etal., Characterization of the neurochemical and behavioral effects ofsolriamfetol (JZP-110), a selective dopamine and norepinephrine reuptakeinhibitor. J Pharmacol Exp Ther. 2018; 366:367-376).

As those of skill may recognize, APC-HCl (also referred to assolriamfetol HCl) has been approved by the FDA and EMA as awake-promoting agent for the treatment of excessive daytime sleepinessassociated with narcolepsy and obstructive sleep apnea (OSA). Phase 3trials conducted with APC-HCl on patients having narcolepsy and OSAdemonstrated statistically significant reductions in excessive daytimesleepiness measured on the patient-reported Epworth Sleepiness Scale andimprovement in objective assessment of wakefulness using the Maintenanceof Wakefulness Test. Significantly higher percentages of participantstreated with APC-HCl in these trials also reported improvement on thePatient Global Improvement of Change scale relative to placebo at allevaluated time points. See, Johns M W, A new method for measuringdaytime sleepiness: the Epworth Sleepiness Scale. Sleep. 1991;14(6):540-545); Thorpy M J, Dauvilliers Y, Shapiro C, et al., Arandomized, placebo-controlled, phase 3 study of the safety and efficacyof JZP-110 for the treatment of excessive sleepiness in patients withnarcolepsy, Sleep, 2017; 40 (suppl): A250; Schweitzer P K, Rosenberg R,Zammit G K, et al., Solriamfetol for excessive sleepiness in obstructivesleep apnea (TONES 3): a randomized controlled trial, Am J Respir CritCare Med. 2018; December 6; and Strollo P J, Jr., Hedner J, Collop N, etal., Solriamfetol for the treatment of excessive sleepiness inobstructive sleep apnea: A placebo-controlled randomized-withdrawalstudy. Chest. 2018; November 21.

The most common adverse reactions or effects associated with APC-HCltherapy include headache, nausea, decreased appetite, anxiety,nervousness, panic attack, dry mouth, and diarrhea. Many of theseeffects can interfere with everyday activities and quality of life. Datafrom 12-week placebo-controlled clinical trials comparing various dosesof solriamfetol support the conclusion that these adverse effects aredose-dependent and that they are exacerbated when APC-HCl isadministered at higher doses. Additionally, solriamfetol has been shownto rely on renal excretion of unchanged drug as its primary route ofelimination. The fact that the mean renal clearance of APC-HCl is 3times the glomerular filtration rate suggest that its renal clearance ismost likely attributed to a combination of passive diffusion and activerenal tubular secretion by multiple cation transporters working inconcert, with minimal tubular reabsorption. Therefore, administration ofAPC-HCl to patients with impaired renal function (which entails reducedpassive diffusion and active renal tubular secretion) would be expectedto result in higher APC-HCl exposure in this patient population. Priorto the present inventor's discovery however, it was not known what dose,if any, or escalation of APC-HCl would be safe for the renally impairedgiven the drug's unique pharmacological profile.

SUMMARY OF THE INVENTION

The present invention addresses an unmet medical need by providingmethods of administering APC-HCl to renally impaired subjects in amanner that minimizes adverse effects. Of the methods provided is a doseescalation scheme for administering APC-HCl to patients with mild renalimpairment, which involves an initial daily dose equivalent to 75 mg APCand waiting until after at least 3 days to reach the maximum daily doseequivalent to 150 mg APC. In another aspect of the invention, the doseescalation scheme of the present invention provides APC-HCl to patientswith moderate renal impairment at an initial daily dose equivalent to37.5 mg APC and in a manner such that maximum dosage is not reacheduntil after at least five days (in some embodiments of the invention, atleast seven days); the method allows for a maximum dosage equivalent to75 mg APC per day to be administered to a patient so as to reduce theincidence of adverse effects associated with the administration ofAPC-HCl by tailoring dose escalation to account for tolerancedevelopment in the patient. For patients with severe renal impairment(who have further reduced passive diffusion and active renal tubularsecretion as compared with moderately impaired patients), the inventionprovides an alternative dosing regimen involving a daily maximum doseequivalent to 37.5 mg APC. The present inventor, based on analyses ofthe pharmacokinetics and safety profile of APC-HCl in conjunction withpopulation PK simulations, has additionally discovered that use ofAPC-HCl should be avoided for patients with end-stage renal disease(with or without hemodialysis).

As such, provided according to embodiments of the present invention aremethods of providing APC-HCl to a renally impaired subject in needthereof according to a dose escalation regimen, the method comprisingproviding to the subject a first oral daily dose equivalent to 37.5 mgAPC from day one to day n₁ of the dose escalation regimen; and providingto the subject a second oral daily dose equivalent to 75 mg APC startingon day n₂ of the dose escalation regimen, wherein n₁ is an integer equalto or greater than 5 and n₂ is equal to the sum of n₁+1, wherein therenally impaired subject is not provided a daily dose exceeding a doseequivalent to 75 mg APC, and wherein the renally impaired subject has anestimated glomerular filtration rate (eGFR) of about 30 mL/min/1.73 m²to about 59 mL/min/1.73 m².

Further provided according to embodiments of the invention are methodsof providing APC-HCl to a renally impaired subject with narcolepsy inneed thereof, the method comprising providing to the subject an oraldaily dose equivalent to 37.5 mg APC, wherein the renally impairedsubject is not provided a daily dose exceeding a dose equivalent 37.5 mgAPC; and wherein the renally impaired subject has an eGFR of about 15ml/min/1.73 m² to about 29 ml/min/1.73 m².

Further provided according to embodiments of the invention are methodsof treating excessive daytime sleepiness in a renally impaired subjectwith narcolepsy in need thereof, comprising administering to the subjectAPC-HCl at an initial dose equivalent to 37.5 mg APC once daily; whereinthe subject has an estimated glomerular filtration rate of 30-59ml/min/1.73 m²; thereby treating excessive daytime sleepiness in thesubject.

Further provided according to embodiments of the invention are methodsof treating excessive daytime sleepiness in a renally impaired subjectwith narcolepsy in need thereof, comprising administering to the subjectAPC-HCl at a maximum dose equivalent to 37.5 mg APC once daily; whereinthe subject has an estimated glomerular filtration rate of 15-29ml/min/1.73 m²; thereby treating excessive daytime sleepiness in thesubject.

Further provided according to embodiments of the invention are methodsof guiding APC therapy in a renally impaired subject with narcolepsy inneed thereof, comprising: (a) determining if the subject has mild renalimpairment (an estimated glomerular filtration rate of 60-89 ml/min/1.73m²), moderate renal impairment (an estimated glomerular filtration rateof 30-59 ml/min/1.73 m²), severe renal impairment (an estimatedglomerular filtration rate of 15-29 ml/min/1.73 m²), or end stage renaldisease (an estimated glomerular filtration rate of less than 15ml/min/1.73 m²); and (b) administering to the subject APC-HCl accordingto a regimen recommended for subjects without renal impairment if thesubject has mild renal impairment, said regimen comprising an initialdose equivalent to 75 mg APC once daily and a maximum dose equivalent to150 mg APC once daily; or administering to the subject APC-HCl at aninitial dose equivalent to 37.5 mg APC once daily and a maximum doseequivalent to 75 mg APC once daily if the subject has moderate renalimpairment; or administering to the subject APC-HCl at a maximum doseequivalent to 37.5 mg APC once daily if the subject has severe renalimpairment; or not administering to the subject APC-HCl if the subjecthas end stage renal disease.

Further provided according to embodiments of the invention are methodsof guiding APC therapy in a renally impaired subject with obstructivesleep apnea in need thereof, comprising: (a) determining if the subjecthas mild renal impairment (an estimated glomerular filtration rate of60-89 ml/min/1.73 m²), moderate renal impairment (an estimatedglomerular filtration rate of 30-59 ml/min/1.73 m²), severe renalimpairment (an estimated glomerular filtration rate of 15-29 ml/min/1.73m²), or end stage renal disease (an estimated glomerular filtration rateof less than 15 ml/min/1.73 m²); and (b) administering to the subjectAPC-HCl according to a regimen recommended for subjects without renalimpairment if the subject has mild renal impairment, said regimencomprising an initial dose equivalent to 37.5 mg APC once daily and amaximum dose equivalent to 150 mg APC once daily; or administering tothe subject APC-HCl at an initial dose equivalent to 37.5 mg APC oncedaily and a maximum dose equivalent to 75 mg APC once daily if thesubject has moderate renal impairment; or administering to the subjectAPC-HCl at a maximum dose equivalent to 37.5 mg APC once daily if thesubject has severe renal impairment; or not administering to the subjectAPC-HCl if the subject has end stage renal disease.

Further provided according to embodiments of the invention are methodsof treating excessive daytime sleepiness in a renally impaired subjectwith obstructive sleep apnea in need thereof, comprising administeringto the subject APC-HCl at an initial dose equivalent to 37.5 mg APC oncedaily, wherein the subject has an estimated glomerular filtration rateof 30-59 ml/min/1.73 m², thereby treating excessive daytime sleepinessin the subject.

Further provided according to embodiments of the invention are methodsof treating excessive daytime sleepiness in a renally impaired subjectwith obstructive sleep apnea in need thereof, comprising administeringto the subject APC-HCl at a maximum dose equivalent to 37.5 mg APC oncedaily; wherein the subject has an estimated glomerular filtration rateof 15-29 ml/min/1.73 m², thereby treating excessive daytime sleepinessin the subject.

Further provided according to embodiments of the invention are methodsof reducing toxicity of APC-HCl therapy in a renally impaired subject,comprising: administering to the subject APC-HCl at an initial doseequivalent to 37.5 mg APC once daily; increasing the daily dose to amaximum dose equivalent to 75 mg APC after at least 7 days; wherein thesubject has an estimated glomerular filtration rate of 30-59 ml/min/1.73m², thereby reducing toxicity of APC-HCl therapy in the subject.

Further provided according to embodiments of the invention are methodsof reducing toxicity of APC-HCl therapy in a renally impaired subject,comprising administering to the subject APC-HCl at a maximum doseequivalent to 37.5 mg APC once daily; wherein the subject has anestimated glomerular filtration rate of 15-29 ml/min/1.73 m², therebyreducing toxicity of APC-HCl in the subject.

Further provided according to embodiments of the invention are methodsof reducing toxicity of APC-HCl therapy in a renally impaired subject,comprising: (a) determining if the subject has mild renal impairment (anestimated glomerular filtration rate of 60-89 ml/min/1.73 m²), moderaterenal impairment (an estimated glomerular filtration rate of 30-59ml/min/1.73 m²), severe renal impairment (an estimated glomerularfiltration rate of 15-29 ml/min/1.73 m²), or end stage renal disease (anestimated glomerular filtration rate of <15 ml/min/1.73 m²); and (b)administering to the subject APC-HCl at a dose of APC-HCl recommendedfor subjects without renal impairment if the subject has mild renalimpairment, wherein the dose of APC-HCl recommended for subjects withoutrenal impairment comprises an initial dose equivalent to 75 mg APC oncedaily and a maximum dose equivalent to 150 mg APC once daily after atleast 3 days; or administering to the subject APC-HCl at an initial doseequivalent to 37.5 mg APC once daily and a maximum dose equivalent to 75mg APC once daily after at least 7 days if the subject has moderaterenal impairment; or administering to the subject APC-HCl at a maximumdose equivalent to 37.5 mg APC once daily if the subject has severerenal impairment; or not administering to the subject APC-HCl if thesubject has end stage renal disease. In some embodiments of theinvention, the subject is being treated with the above dosing regimenfor excessive daytime sleepiness associated with narcolepsy.

In other embodiments of the invention, methods of reducing toxicity ofAPC-HCl therapy in a renally impaired subject with obstructive sleepapnea comprise: (a) determining if the subject has mild renal impairment(an estimated glomerular filtration rate of 60-89 ml/min/1.73 m²),moderate renal impairment (an estimated glomerular filtration rate of30-59 ml/min/1.73 m²), severe renal impairment (an estimated glomerularfiltration rate of 15-29 ml/min/1.73 m²), or end stage renal disease (anestimated glomerular filtration rate of <15 ml/min/1.73 m²); and (b)administering to the subject APC-HCl at a dose of APC-HCl recommendedfor subjects without renal impairment if the subject has mild renalimpairment, wherein the dose of APC-HCl recommended for subjects withoutrenal impairment comprises an initial dose equivalent to 37.5 mg APConce daily and doubling the dose at intervals of at least 3 days to amaximum dose equivalent to 150 mg APC; or administering to the subjectAPC-HCl at an initial dose equivalent to 37.5 mg APC once daily and amaximum dose equivalent to 75 mg APC once daily after at least 7 days ifthe subject has moderate renal impairment; or administering to thesubject APC-HCl at a maximum dose equivalent to 37.5 mg APC once dailyif the subject has severe renal impairment; or not administering to thesubject APC-HCl if the subject has end stage renal disease.

The present invention is explained in greater detail in the drawingsherein and the specification set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows the mean (SD) plasma of APC-HCl concentration-timeprofiles following a single dose equivalent to 75-mg APC forparticipants with normal renal function and mild-to-severe renalimpairment.

FIG. 1B shows the mean (SD) plasma APC-HCl concentration-time profilesfollowing a single dose equivalent to 75-mg APC for participants withend-stage renal disease with and without hemodialysis.

FIG. 2 shows the apparent oral clearance (CL/F) versus day-1 estimatedglomerular filtration rate (eGFR) for Groups 1-4. The broken linesrepresent the 90% confidence intervals.

FIG. 3 shows results of simulations to support dosing insub-populations—comparison of exposure in adult patients(narcolepsy/OSA, tablet, fasting conditions) by renal function—AUCtau.

FIG. 4 shows the results of simulations to support dosing insub-populations—comparison of exposure in adult patients(Narcolepsy/OSA, tablet, fasting conditions) by renal function—C max.

FIG. 5 shows the results of simulations to support dosing insub-populations—comparison of exposure in adult patients(Narcolepsy/OSA, tablet, fasting conditions) by renal function—C min.

FIG. 6 shows the results of simulations to support dosing insub-populations—comparison of exposure in adult patients(Narcolepsy/OSA, tablet, fasting conditions) by renal function—C14h.

FIG. 7 shows the results of simulations to support dosing insub-populations—comparison of exposure in adult patients(Narcolepsy/OSA, tablet, fasting conditions) by renalfunction—half-life.

FIG. 8 shows the results of simulations to support dosing insub-populations—adult patients (Narcolepsy/OSA, tablet, fastingconditions)—individual PK profile (Semi-Log Scale).

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art. For example, features illustrated with respect toone embodiment can be incorporated into other embodiments, and featuresillustrated with respect to a particular embodiment can be deleted fromthat embodiment. In addition, numerous variations and additions to theembodiments suggested herein will be apparent to those skilled in theart in light of the instant disclosure, which do not depart from theinstant invention.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The terminology used in thedescription of the invention herein is for the purpose of describingparticular embodiments only and is not intended to be limiting of theinvention.

Unless the context indicates otherwise, it is specifically intended thatthe various features of the invention described herein can be used inany combination.

Moreover, the present invention also contemplates that in someembodiments of the invention, any feature or combination of features setforth herein can be excluded or omitted.

To illustrate, if the specification states that a complex comprisescomponents A, B and C, it is specifically intended that any of A, B orC, or a combination thereof, can be omitted and disclaimed singularly orin any combination.

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference herein in their entiretyfor all purposes.

As used herein, “a,” “an,” or “the” can mean one or more than one. Forexample, “a” cell can mean a single cell or a multiplicity of cells.

Also as used herein, “and/or” refers to and encompasses any and allpossible combinations of one or more of the associated listed items, aswell as the lack of combinations when interpreted in the alternative(“or”).

Furthermore, the term “about,” as used herein when referring to ameasurable value such as an amount of a compound or agent of thisinvention, dose, time, temperature, and the like, is meant to encompassvariations of ±10%, ±5%, ±1%, ±0.5%, or even ±0.1% of the specifiedamount.

The term “consists essentially of” (and grammatical variants), asapplied to the compositions of this invention, means the composition cancontain additional components as long as the additional components donot materially alter the composition. The term “materially altered,” asapplied to a composition, refers to an increase or decrease in thetherapeutic effectiveness of the composition of at least about 20% ormore as compared to the effectiveness of a composition consisting of therecited components.

The term “therapeutically effective amount” or “effective amount,” asused herein, refers to that amount of a composition, compound, or agentof this invention that imparts a modulating effect, which, for example,can be a beneficial effect, to a subject afflicted with a disorder,disease or illness, including improvement in the condition of thesubject (e.g., in one or more symptoms), delay or reduction in theprogression of the condition, prevention or delay of the onset of thedisorder, and/or change in clinical parameters, disease or illness,etc., as would be well known in the art. For example, a therapeuticallyeffective amount or effective amount can refer to the amount of acomposition, compound, or agent that improves a condition in a subjectby at least 5%, e.g., at least 10%, at least 15%, at least 20%, at least25%, at least 30%, at least 35%, at least 40%, at least 45%, at least50%, at least 55%, at least 60%, at least 65%, at least 70%, at least75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least100%.

“Treat” or “treating” or “treatment” refers to any type of action thatimparts a modulating effect, which, for example, can be a beneficialeffect, to a subject afflicted with a disorder, disease or illness,including improvement in the condition of the subject (e.g., in one ormore symptoms), delay or reduction in the progression of the condition,and/or change in clinical parameters, disease or illness, etc., as wouldbe well known in the art.

“Pharmaceutically acceptable,” as used herein, means a material that isnot biologically or otherwise undesirable, i.e., the material can beadministered to an individual along with the compositions of thisinvention, without causing substantial deleterious biological effects orinteracting in a deleterious manner with any of the other components ofthe composition in which it is contained. The material would naturallybe selected to minimize any degradation of the active ingredient and tominimize any adverse side effects in the subject, as would be well knownto one of skill in the art (see, e.g., Remington's PharmaceuticalScience; 21^(st) ed. 2005).

“Concurrently” means sufficiently close in time to produce a combinedeffect (that is, concurrently can be simultaneously, or it can be two ormore events occurring within a short time period before or after eachother). In some embodiments, the administration of two or more compounds“concurrently” means that the two compounds are administered closelyenough in time that the presence of one alters the biological effects ofthe other. The two compounds can be administered in the same ordifferent formulations or sequentially. Concurrent administration can becarried out by mixing the compounds prior to administration, or byadministering the compounds in two different formulations, for example,at the same point in time but at different anatomic sites or usingdifferent routes of administration.

The compound [R]-2-amino-3-phenylpropylcarbamate (APC) or solriamfetolis also named (R)-(beta-amino-benzenepropyl) carbamate orO-carbamoyl-(D)-phenylalaninol and has alternatively been calledADX-N05, SKL-N05, SK-N05, YKP10A, and R228060. The hydrochloride salt ofthe compound is named [R]-2-amino-3-phenylpropylcarbamate hydrochloride(APC-HCl) or solriamfetol HCl.

A “disorder or condition amenable to treatment” refers to any disorderor condition in which administration of APC to a subject results in thetreatment of one or more symptoms of the disorder in the subject.Disorders amenable to treatment with APC include, without limitation,excessive daytime sleepiness, fatigue, drug addiction, sexualdysfunction, depression, fibromyalgia syndrome, attentiondeficit/hyperactivity disorder, restless legs syndrome, bipolardisorder, cataplexy, obesity, and smoking cessation.

In some embodiments, APC may be used to treat and/or prevent excessivedaytime sleepiness (EDS). See U.S. Pat. Nos. 8,440,715; 8,877,806;9,604,917; and 10,351,517; incorporated by reference herein in theirentirety. EDS may be due to, without limitation, a central nervoussystem (CNS) pathologic abnormality, stroke, narcolepsy, idiopathic CNShypersomnia, sleep deficiency, sleep apnea, obstructive sleep apnea,insufficient nocturnal sleep, chronic pain, acute pain, Parkinson'sdisease, urinary incontinence, multiple sclerosis fatigue, attentiondeficit hyperactivity disorder, Alzheimer's disorder, bipolar disorder,cardiac ischemia, misalignments of the body's circadian pacemaker withthe environment, or jet lag; or a subject doing shift work or takingsedating drugs.

In some embodiments, APC may be used to treat and/or prevent fatigue.See U.S. Pat. Nos. 8,741,950; 9,464,041; 9,999,609; and 10,507,192;incorporated by reference herein in their entirety. Fatigue may be dueto, without limitation, a disease, disorder or condition such asdepression, cancer, multiple sclerosis, Parkinson's disease, Alzheimer'sdisease, chronic fatigue syndrome, fibromyalgia, chronic pain, traumaticbrain injury, AIDS, and osteoarthritis. Fatigue may be due to, withoutlimitation, a treatment or medication such as chemotherapy, radiationtherapy, bone marrow transplant, and anti-depressant treatment.

In some embodiments, APC may be used to treat drug addiction. See U.S.Pat. No. 8,232,315, incorporated by reference in its entirety. In someembodiments, the addicted drug may be nicotine, opioid, cocaine,amphetamine, methamphetamine, ethanol, heroin, morphine, phencyclidine(PCP), and methylenedioxymethamphetamine (MDMA).

In some embodiments, APC may be used to treat sexual dysfunction. SeeU.S. Pat. No. 8,552,060, incorporated by reference herein in itsentirety. In some embodiments, the treatment may increase interest insex and/or the ability to have an orgasm. In some embodiments, thesexual dysfunction may be due to treatment with a therapeutic agent,including without limitation, selective serotonin reuptake inhibitors(SSRIs); selective serotonin and norepinephrine reuptake inhibitors(SNRIs); older tricyclic antidepressants (TCAs); monoamine oxidaseinhibitors (MAO-inhibitors), reversible inhibitors of monoamine oxidase(RIMAs), tertiary amine tricyclics and secondary amine tricyclicantidepressants, e.g., therapeutic agents such as fluoxetine,duloxetine, venlafaxine, milnacipran, citalopram, fluvoxamine,paroxetine, sertraline, 5-MCA-NAT, lithium carbonate, isocarboxazid,phenelzine, tranylcypromine, selegiline, moclobemide, kappa opioidreceptor antagonists; selective neurokinin antagonists, corticotropinreleasing factor (CRF) antagonists, antagonists of tachykinins,α-adrenoreceptor antagonists, amitriptyline, clomipramine, doxepin,imipramine, venlafaxine, trimipramine, amoxapine, desipramine,maprotiline, nortriptyline and protriptyline, and pharmaceuticallyacceptable salts thereof.

In some embodiments, APC may be used as an adjunctive therapy to treatdepression. See U.S. Pat. No. 8,729,120, incorporated by referenceherein in its entirety. In some embodiments, APC is administered to asubject in conjunction with an antidepressant such as, withoutlimitation, fluoxetine, amitriptyline, clomipramine, doxepin,imipramine, trimipramine or a pharmaceutically acceptable salt thereof.

In some embodiments, APC may be used to treat fibromyalgia syndrome. SeeU.S. Pat. Nos. 8,927,602 and 9,688,620; incorporated by reference hereinin their entirety.

In some embodiments, APC may be used to treat attentiondeficit/hyperactivity disorder (ADHD) or diminish symptoms associatedwith ADHD. See U.S. Pat. Nos. 8,895,609; 9,663,455; and 10,202,335;incorporated by reference herein in their entirety.

In some embodiments, APC may be used to treat restless legs syndrome.See U.S. Pat. No. 8,623,913, incorporated by reference herein in itsentirety.

In some embodiments, APC may be used to treat bipolar disorder. See U.S.Pat. Nos. 9,610,274 and 9,907,777; incorporated by reference herein intheir entirety. In some embodiments, APC may be used to diminish manicsymptoms in a subject suffering from bipolar disorder.

In some embodiments, APC may be used to treat cataplexy. See U.S. Pat.Nos. 9,359,290; 9,585,863; and 10,259,780; incorporated by referenceherein in their entirety. In some embodiments, the cataplexy issecondary to a condition that lowers hypocretin levels in a subject,such as a brain tumor, astrocytoma, glioblastoma, glioma, subependynoma,craniopharyngioma, arterio-venous malformations, ischemic events,multiple sclerosis, head injury, brain surgery, paraneoplasticsyndromes, Neimann-Pick type C disease, or encephalitis.

In some embodiments, APC may be used to treat obesity, reduce bodyweight, reduce or prevent body weight gain, reduce food intake, or treatpathological eating. See U.S. Pat. Nos. 9,226,910; 9,649,291; and10,105,341; incorporated by reference herein in their entirety.

In some embodiments, APC may be used to promote cessation or reductionin the smoking and/or chewing of tobacco or nicotine-containing productsand/or to prevent relapse of the same. See US Publication No.2015/0018414, incorporated by reference herein in its entirety.

Methods of Treating Excessive Daytime Sleepiness

Provided according to embodiments of the present invention are methodsof treating excessive daytime sleepiness in a renally impaired subjectin need thereof, comprising administering to the subject an APC salt,such as APC-HCl. In some embodiments, such methods compriseadministering to the subject an APC salt at an initial dose equivalentto 37.5 mg APC once daily, wherein the subject has an eGFR of 30-59ml/min/1.73 m², thereby treating excessive daytime sleepiness in thesubject. In particular embodiments, such methods further includeincreasing the dose to a maximum equivalent of 75 mg APC once dailyafter at least 7 days. In some embodiments of the invention, the subjecthas narcolepsy, OSA, or both.

Further provided according to some embodiments of the invention aremethods of treating excessive daytime sleepiness in a renally impairedsubject in need thereof that comprise administering to the subject anAPC salt, such as APC-HCl, at a maximum dose equivalent to 37.5 mg APConce daily; wherein the subject has an eGFR of 15-29 ml/min/1.73 m²;thereby treating excessive daytime sleepiness in the subject.

Further provided according to embodiments of the invention are methodsof guiding the treatment of excessive daytime sleepiness in a renallyimpaired subject in need thereof, comprising:

(a) determining if the subject has mild renal impairment (an eGFR of60-89 ml/min/1.73 m²), moderate renal impairment (an eGFR of 30-59ml/min/1.73 m²), severe renal impairment (an eGFR of 15-29 ml/min/1.73m²), or end stage renal disease (an eGFR of <15 ml/min/1.73 m²); and

(b) administering to the subject the dose of an APC salt (e.g., APC-HCl)recommended for subjects without renal impairment if the subject hasmild renal impairment; or administering to the subject an APC salt at aninitial dose equivalent to 37.5 mg APC once daily and a maximum doseequivalent to 75 mg APC once daily if the subject has moderate renalimpairment; or administering to the subject an APC salt at a maximumdose equivalent to 37.5 mg APC once daily if the subject has severerenal impairment; or not administering to the subject an APC salt if thesubject has end stage renal disease.

In some embodiments, the methods further comprise measuring the eGFR inthe subject prior to step (a).

Also provided according to other embodiments of the present inventionare methods of reducing toxicity of an APC salt (e.g., APC-HCl) in arenally impaired subject, comprising administering to the subject theAPC salt at an initial dose equivalent to 37.5 mg APC once daily,wherein the subject has an eGFR of 30-59 ml/min/1.73 m², therebyreducing toxicity of the APC salt. In particular embodiments, suchmethods further include increasing the dose to a maximum equivalent of75 mg APC once daily after at least 7 days. “Reducing toxicity,” as usedherein, refers to reducing the number and/or severity of adversereactions or effects associated with APC-HCl therapy relative to thenumber and/or severity of adverse reactions or effects in the absence ofthe methods of the invention.

Provided according to some embodiments of the present invention aremethods of reducing toxicity of an APC salt (e.g., APC-HCl) in a renallyimpaired subject, such methods comprising administering to the subjectan APC salt at a maximum dose equivalent to 37.5 mg APC once daily,wherein the subject has an eGFR of 15-29 ml/min/1.73 m², therebyreducing the toxicity of the APC salt in the subject.

Further, provided according to embodiments of the present invention aremethods of reducing toxicity of an APC salt in a renally impairedsubject, comprising:

(a) determining if the subject has mild renal impairment (an eGFR of60-89 ml/min/1.73 m²), moderate renal impairment (an eGFR of 30-59ml/min/1.73 m²), severe renal impairment (an eGFR of 15-29 ml/min/1.73m²), or end stage renal disease (an eGFR of <15 ml/min/1.73 m²); and

(b) administering to the subject the dose of an APC salt recommended forsubjects without renal impairment if the subject has mild renalimpairment; or administering to the subject an APC salt at an initialdose equivalent to 37.5 mg APC once daily and a maximum dose equivalentto 75 mg APC once daily if the subject has moderate renal impairment; oradministering to the subject an APC salt at a maximum dose equivalent to37.5 mg APC once daily if the subject has severe renal impairment; ornot administering to the subject an APC salt if the subject has endstage renal disease. In some embodiments, the methods further comprisemeasuring the estimated glomerular filtration rate in the subject priorto step (a).

The methods of the invention may be used to treat any disorder orcondition amenable to treatment with APC. Disorders amenable totreatment with APC include, without limitation, excessive daytimesleepiness, fatigue, sleep apnea, drug addiction, sexual dysfunction,depression, fibromyalgia syndrome, attention deficit/hyperactivitydisorder, restless legs syndrome, bipolar disorder, cataplexy, obesity,as well as induction of smoking cessation.

Excessive Daytime Sleepiness

“Excessive daytime sleepiness” or “EDS” refers to persistent sleepinessat a time when the individual would be expected to be awake and alert,even during the day after apparently adequate or even prolongednighttime sleep. EDS may be the result of a sleep disorder or a symptomof another underlying disorder such as narcolepsy, sleep apnea,circadian rhythm sleep disorder, or idiopathic hypersomnia. While thename includes “daytime,” it is understood that the sleepiness may occurat other times that the subject should be awake, such as nighttime orother times, e.g., if the subject is working nightshift.

In some embodiments of the invention, treating excessive daytimesleepiness in a subject in need thereof may result in the decrease thesubject's score on the Epworth Sleepiness Scale (ESS) by 5 or morepoints, e.g., by 10 or more points, e.g., by 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or more points or anyrange therein. In some embodiments, the amount of APC salt administeredis sufficient to decrease the subject's score on the ESS to a level thatis considered normal, e.g., 10 or less. In certain embodiments, at leastabout 5% of the treated subjects achieve the specified score, e.g., atleast about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, or more.

The ESS is a subjective sleepiness test that is well known in the artand routinely used to measure the sleepiness level of a subject. Thescale is intended to measure daytime sleepiness through the use of ashort questionnaire that asks the subject to rate his or her probabilityof falling asleep on a scale of increasing probability from 0 to 3 foreight different situations that most people engage in during their dailylives. The scores for the eight questions are added together to obtain asingle number that estimates the subject's average sleep propensity(ASP). A number in the 0-10 range is considered to be normal while 11-12indicates mild excessive sleepiness, 13-15 indicates moderate excessivesleepiness, and 16 or higher indicates severe excessive sleepiness.Narcolepsy patients have an average score of about 17. Obstructive sleepapnea (OSA) patients with excessive sleepiness have an average score ofabout 15.

In some cases, treating excessive daytime sleepiness in a subject inneed thereof results in an increase the subject's score on themaintenance of wakefulness test (MWT) by at least 5 minutes, e.g., atleast 10 minutes or 15 minutes, e.g., at least 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,27, 28, 29, or 30 minutes or more or any range therein. In certainembodiments, at least about 5% of the treated subjects achieve thespecified score, e.g., at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or more.

The MWT is an objective test used to measure how alert a subject isduring the day. The test consists of four sleep trials with two hours inbetween the trials. The first trial is performed 1.5-3 hours after thesubject's normal wake-up time. Sensors are placed on the head, face, andchin to detect when the subject is asleep and awake during the test. Thesubject sits quietly in bed with his or her back and head supported by apillow and is asked to sit still and look straight ahead while trying tostay awake as long as possible. Each trial lasts 40 minutes or until thesubject is asleep for 90 seconds. Between trials, the subject stays outof bed and occupies himself or herself to remain awake. Falling asleepin an average of less than eight minutes is considered abnormal. About40-60% of subjects with normal sleep stay awake for the entire 40minutes of all four trials.

The baseline measurement for determining a change in test results, suchas ESS and MWT, may be performed before the subject has beenadministered APC or at a timepoint during a course of treatment of APCat which a baseline determination is desired. One or more subsequentdeterminations of test results may be made at any time afteradministration of one or more doses of APC. For example, determinationof a change in test results may be made 1, 2, 3, 4, 5, or 6 days or 1,2, 3, 4, 5, 6, 7, 8, 9, or 10 weeks after the administration of APC hasbegun or after the baseline determination was made.

The methods of the invention may be effective no matter the cause of theEDS, but in some embodiments of the invention, the EDS is associatedwith narcolepsy or obstructive sleep apnea (OSA). In other embodiments,the cause of the EDS may be, without limitation, central nervous system(CNS) pathologic abnormalities, stroke, idiopathic CNS hypersomnia;sleep deficiency, other sleep apnea, insufficient nocturnal sleep,chronic pain, acute pain, Parkinson's disease, urinary incontinence,multiple sclerosis fatigue, attention deficit hyperactivity disorder(ADHD), Alzheimer's disorder, major depression, bipolar disorder,cardiac ischemia; misalignments of the body's circadian pacemaker withthe environment, jet lag, shift work, or sedating drugs.

The methods of the invention may also be used to increase wakefulnessand/or alertness in a subject in need thereof.

Renal Impairment

In embodiments of the present invention, the renal status of the subjectmay be determined by measuring the “estimated glomerular filtrationrate” or “eGFR” of the individual. The eGFR in mL/min/1.73 m² iscalculated by the Modification of Diet in Renal Disease [MDRD] equation:(eGFR in mL/min)/1.73 m²=175×(serum creatinine inmg/dL)^(−1.154)×Age^(−0.203)×0.742(if female)×1.212(if black).

Further details regarding the calculation of the eGFR may be found in,e.g., Levey A S, Coresh J, Greene T, Marsh J, Stevens L A, Kusek J W,Van Lente F: Chronic Kidney Disease Epidemiology Collaboration.Expressing the Modification of Diet in Renal Disease Study Equation forEstimating Glomerular Filtration Rate with Standardized Serum CreatinineValues. Ann Intern Med. 2009; 150(9):604-12.

Renal impairment status based on Food and Drug Administration (FDA)guidance is as follows.

-   -   Normal: eGFR≥90 mL/min/1.73 m²    -   Mild: eGFR 60-89 mL/min/1.73 m2 (i.e., ≥60 to <90)    -   Moderate: eGFR 30-59 mL/min/1.73 m² (i.e., ≥30 to <60)    -   Severe: eGFR 15-29 mL/min/1.73 m² (i.e., ≥15 to <30) and not on        hemodialysis    -   End-stage renal disease (ESRD): eGFR<15 mL/min/1.73 m² and not        on hemodialysis or on hemodialysis        See, Guidance for Industry Pharmacokinetics in Patients with        Impaired Renal Function—Study Design, Data Analysis and Impact        on Dosing and Labeling. U.S. Department of Health and Human        Services Food and Drug Administration Center for Drug Evaluation        and Research (CDER) Center for Biologics Evaluation and Research        (CBER) February 2010. As used herein, a “renally impaired        subject” may have mild, moderate, or severe renal impairment, or        may have ESRD.        APC Salts

The methods of the present invention may be carried out using compounds,formulations and unit dosage forms provided herein. In some embodiments,the formulations and dosage forms may include pharmaceuticallyacceptable salts of APC (“APC salt”), which also includes hydrates,solvates, clathrates, inclusion compounds, and complexes thereof.

In some embodiments of the invention, the APC salt is a hydrochloridesalt (APC-HCl). However, suitable salts of APC also include, withoutlimitation, acetate, adipate, alginate, aspartate, benzoate, butyrate,citrate, fumarate, glycolate, hemisulfate, heptanoate, hexanoate,hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate,malonate, methanesulfonate, nicotinate, nitrate, oxalate, palmoate,pectinate, persulfate, hydroxynapthoate, pivalate, propionate,salicylate, succinate, sulfate, tartrate, thiocyanate, tosylate andundecanoate. Other acids, such as oxalic, while not in themselvespharmaceutically acceptable, can be employed in the preparation of saltsuseful as intermediates in obtaining the compound of the invention andtheir pharmaceutically acceptable acid addition salts. APC salts includethose having quaternization of any basic nitrogen-containing grouptherein.

The discussion herein is, for simplicity, provided without reference tothe addition of deuterium atoms, but the APC salts may further includenon-ordinary isotopes. Those skilled in the art will appreciate that theAPC salt can contain one or more asymmetric centers and thus occur asracemates and racemic mixtures and single optical isomers. Inembodiments of the present invention, the APC salt stereoisomer ispreferred, but formulations according to embodiments of the inventionmay include both (R) and (S) isomers in a racemic mixture, or in anyratio of the isomers. In particular embodiments, the(R)-2-amino-3-phenylpropyl carbamate salt stereoisomer is present at agreater concentration than the (S)-2-amino-3-phenylpropyl carbamate saltstereoisomer, and in some embodiments, the formulation includes the2-amino-3-phenylpropyl carbamate salt as a substantiallyenantiomerically pure (R)-2-amino-3-phenylpropyl carbamate saltstereoisomer such as having an enantiomeric excess of greater than 80%,90%, 95%, or 99%. In some embodiments, the (R)-2-amino-3-phenylpropylcarbamate salt is enantiomerically pure, and in some cases isenantiomerically pure (R)-2-amino-3-phenylpropyl carbamatehydrochloride. When the (R)-2-amino-3-phenylpropyl carbamate salt isreferenced specifically, it is understood that the dosage (e.g., 37.5 mgor 75 mg) refers to the equivalent weight of the (R) enantiomer only.

The APC salt(s) may be obtained or synthesized by methods known in theart and as described herein. Details of reaction schemes forsynthesizing APC have been described in U.S. Pat. Nos. 5,705,640;5,756,817; 5,955,499; and 6,140,532, all incorporated herein byreference in their entirety.

APC Salt Formulations

Any suitable dosage form comprising the APC salts may be used in themethods of the invention. In some embodiments, the dosage formulationcomprises the APC salt (which is pharmaceutically acceptable) and apharmaceutically acceptable carrier. In some embodiments, the dosageform is an oral dosage form, e.g., a tablet or a capsule, e.g., animmediate release dosage form.

In some embodiments, the dosage form is an immediate release tablet thatreleases at least 85%, e.g., at least 85%, 90%, 95%, 96%, 97%, 98%, or99%, of the APC salt contained therein within a period of less than 15minutes after administration of the tablet to a subject. See, forexample, U.S. Pat. No. 10,195,151, incorporated herein by reference inits entirety.

Formulations of the APC salt, including immediate release formulations,may be processed into unit dosage forms suitable for oraladministration, such as for example, filled capsules, compressed tabletsor caplets, or other dosage form suitable for oral administration usingconventional techniques. Immediate release dosage forms prepared asdescribed may be adapted for oral administration, so as to attain andmaintain a therapeutic level of the compound over a preselectedinterval. In certain embodiments, an immediate release dosage form asdescribed herein may comprise a solid oral dosage form of any desiredshape and size including round, oval, oblong cylindrical, or polygonal.In one such embodiment, the surfaces of the immediate release dosageform may be flat, round, concave, or convex. In some embodiments, theshape may be selected to maximize surface area, e.g., to increase therate of dissolution of the dosage form.

In particular, when the immediate release formulations are prepared as atablet, the immediate release tablets may contain a relatively largepercentage and absolute amount of the compound and so may be expected toimprove patient compliance and convenience by replacing the need toingest large amounts of liquids or liquid/solid suspensions. One or moreimmediate release tablets as described herein can be administered, byoral ingestion, e.g., closely spaced, in order to provide atherapeutically effective dose of the compound to the subject in arelatively short period of time.

Where desired or necessary, the outer surface of an immediate releasedosage form may be coated, e.g., with a color coat or with a moisturebarrier layer using materials and methods known in the art.

In some embodiments, the dosage formulation is an immediate releasecompressed tablet, the tablet comprising: the APC salt thereof in anamount of about 90-98% by weight of the tablet; at least one binder inan amount of about 1-5% by weight of the tablet; and at least onelubricant in an amount of about 0.1-2% by weight of the tablet; whereinthe tablet releases at least 85% of the APC or a pharmaceuticallyacceptable salt thereof contained therein within a period of less than15 minutes after administration of the tablet to a subject.

In one embodiment, the tablet comprises: the APC salt thereof in anamount of about 91-95% by weight of the tablet; at least one binder inan amount of about 2-3% by weight of the tablet; at least one lubricantin an amount of about 0.1-1% by weight of the tablet; and optionally, acosmetic film coat in an amount of about 3-4% by weight of the tablet;wherein the tablet releases at least 85% of the APC or apharmaceutically acceptable salt thereof contained therein within aperiod of less than 15 minutes after administration of the tablet to asubject.

In one embodiment, the tablet comprises: the APC salt thereof in anamount of about 93.22% by weight of the tablet; at least one binder(e.g., hydroxypropylcellulose) in an amount of about 2.87% by weight ofthe tablet; at least one lubricant (e.g., magnesium stearate) in anamount of about 0.52% by weight of the tablet; and optionally, acosmetic film coat (e.g., Opadry® II yellow) in an amount of about 3-4%by weight of the tablet; wherein the tablet releases at least 85% of theAPC salt thereof contained therein within a period of less than 15minutes after administration of the tablet to a subject.

In some embodiments, the composition is an immediate release oral dosageform of an APC salt, the oral dosage form comprising: the APC saltthereof in an amount of about 90-98% by weight of the oral dosage form;at least one binder in an amount of about 1-5% by weight of the oraldosage form; and at least one lubricant in an amount of about 0.1-2% byweight of the oral dosage form; wherein the oral dosage form releases atleast 85% of the APC salt thereof contained therein within a period ofless than 15 minutes after administration of the oral dosage form to asubject.

In certain embodiments, the tablet does not comprise a disintegrant. Theterm “disintegrant,” as used herein, refers to an agent added to atablet to promote the breakup of the tablet in an aqueous environment.The tablets of the present invention are advantageous in that theydissolve rather than disintegrate. In the present invention the presenceof disintegrant in the formulation may actually slow down release ofAPC.

In certain embodiments, the APC salt is present in an amount of about90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%,96%, 96.5%, 97%, 97.5%, or 98% by weight of the tablet or any value orrange therein. In certain embodiments, the APC salt thereof is presentin an amount of about 90% to about 98%, about 92% to about 98%, about94% to about 98%, about 96% to about 98%, about 90% to about 92%, about90% to about 94%, about 90% to about 96%, about 92% to about 94%, about92% to about 96%, or about 94% to about 96%.

In certain embodiments, the at least one binder is present in an amountof about 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% by weight of thetablet or any value or range therein. In certain embodiments, the atleast one binder is present in an amount of about 1% to about 5%, about2% to about 5%, about 3% to about 5%, about 4% to about 5%, about 1% toabout 2%, about 1% to about 3%, about 1% to about 4%, about 2% to about3%, about 2% to about 4%, or about 3% to about 4%. The tablet maycomprise at least one binder, e.g., 1, 2, 3, 4, 5, or more binders.

In certain embodiments, the at least one binder is selected from atleast one of hydroxypropyl cellulose, ethylcellulose, hydroxypropylmethylcellulose, polyvinyl alcohol, hydroxyethyl cellulose, povidone,copovidone, pregelatinized starch, dextrin, gelatin, maltodextrin, zein,acacia, alginic acid, carbomers (cross-linked polyacrylates),polymethacrylates, sodium carboxymethylcellulose, guar gum, hydrogenatedvegetable oil (type 1), methylcellulose, magnesium aluminum silicate,and sodium alginate or any combination thereof. In some embodiments, theat least one binder is hydroxypropyl cellulose.

In certain embodiments, the at least one lubricant is present in anamount of about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%,1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2.0% byweight of the tablet or any value or range therein. In certainembodiments, the at least one lubricant is present in an amount of about0.1% to about 2.0%, about 0.5% to about 2.0%, about 1.0% to about 2.0%,about 1.5% to about 2.0%, about 0.1% to about 0.5%, about 0.1% to about1.0%, about 0.1% to about 1.5%, about 0.5% to about 1.0%, about 0.5% toabout 1.5%, or about 1.0% to about 1.5%. The tablet may comprise atleast one lubricant, e.g., 1, 2, 3, 4, 5, or more lubricants. Where theimmediate release formulation is provided as a tableted dosage form,still lower lubricant levels may be achieved with use of a “puffer”system during tableting. Such systems are known in the art, commerciallyavailable and apply lubricant directly to the punch and die surfacesrather than throughout the formulation.

In certain embodiments, the at least one lubricant is selected from atleast one of magnesium stearate, stearic acid, calcium stearate,hydrogenated castor oil, hydrogenated vegetable oil, light mineral oil,magnesium stearate, mineral oil, polyethylene glycol, sodium benzoate,sodium stearyl fumarate, and zinc stearate or any combination thereof.In some embodiments, the at least one lubricant is magnesium stearate.In other embodiments, magnesium stearate may be used in combination withone or more other lubricants or a surfactant, such as sodium laurylsulfate. In particular, if needed to overcome potential hydrophobicproperties of magnesium stearate, sodium lauryl sulfate may also beincluded when using magnesium stearate (Remington: the Science andPractice of Pharmacy, 20^(th) edition, Gennaro, Ed., Lippincott Williams& Wilkins (2000)).

In some embodiments, the at least one binder is hydroxypropyl cellulose.In some embodiments, the at least one lubricant is magnesium stearate.In some embodiments, the at least one binder is hydroxypropyl celluloseand the at least one lubricant is magnesium stearate.

In certain embodiments, the tablet is coated. The coating may be,without limitation, a color overcoat.

The tablet may be any shape that is suitable for immediate release andallows the release of at least 85% of the APC salt contained thereinwithin a period of less than 15 minutes after administration of thetablet to a subject. In some embodiments, the tablet maximizes surfacearea to volume ratio to promote rapid dissolution. In some embodiments,the tablet is oblong in shape.

The tablet may contain any amount of the APC salt suitable foradministration as a unit dosage form. In some embodiments, the tabletcontains the equivalent of about 1 mg to about 1000 mg of APC or anyrange or value therein, e.g., about 100 mg to about 500 mg, e.g., about37.5 mg, about 75 mg, about 150 mg, or about 300 mg.

“Immediate release” as used herein, refers to a composition thatreleases the APC salt substantially completely into the gastrointestinaltract of the user within a period of less than about 15 minutes, usuallybetween about 1 minute and about 15 minutes from ingestion. Such adelivery rate allows the drug to be absorbed by the gastrointestinaltract in a manner that is bioequivalent to an oral solution. Such rapidabsorption will typically occur for an immediate release unit dosageform, such as a tablet, caplet or capsule, if the drug included in suchdosage form dissolves in the upper portion the gastrointestinal tract.

Release rates can be measured using standard dissolution test methods.For example, the standard conditions may be those described in FDAguidance (e.g., 50 rpm, 37° C., USP 2 paddles, pH 1.2 and pH 6.8 media,900 ml, 1 test article per vessel).

Immediate release formulations suitable for oral administration maycomprise unit dosage forms, such as tablets, caplets or filled capsules,which can deliver a therapeutically effective dose of the APC salt uponingestion thereof by the patient of one or more of said dosage forms,each of which can provide a dosage of, for example, about 37.5 mg toabout 75 mg, or 75 mg to about 150 mg of APC. Additionally, theimmediate release dosage forms can be shaped or scored to facilitatedose adjustment through tablet splitting. For example, a 75 mg APCtablet or caplet may be scored to facilitate tablet splitting into two37.5 mg APC doses.

The formulation and structure of an immediate release dosage form asdisclosed herein can be adjusted to provide immediate releaseperformance that suits a particular dosing need. In particular, theformulation and structure of the dosage forms as described herein can beadjusted to provide any combination of the immediate release performancecharacteristics described herein. In particular embodiments, forexample, an immediate release dosage form as disclosed herein providesrapid onset of action, releasing more than about 85%, such as, forexample, more than about 90% or 95%, of the drug contained thereinwithin a period of time selected from less than 15 minutes, less than 12minutes, less than 10 minutes, and less than 5 minutes afteradministration.

Moreover, the rate of drug release from an immediate release dosage formas disclosed herein may be adjusted as needed to facilitate a desireddosing regimen or achieve targeted dosing. In certain such embodiments,the total amount of the APC salt in the dosage formulation may includean equivalent dose of about 10 mg to about 300 mg APC, about 30 mg toabout 300 mg APC, about 100 mg to about 300 mg APC, or about 150 mg toabout 300 mg APC, about 75 to 150 mg APC, about 37.5 to about 75 mg APC,and about 37.5 to about 150 mg APC. In particular embodiments, theequivalent dose of APC in the dosage formulation is 37.5 mg, and inother particular embodiments, the equivalent dose of APC in the dosageformulation is 75 mg. In some cases, such dosage formulations may beformed (e.g., scoring) to facilitate creating more than one dose from aparticular dosage form.

The immediate release formulations provided herein generally include theAPC salt and some level of lubricant to facilitate processing of theformulations into a unit dosage form. In some embodiments, therefore,the formulations described herein include a combination of the APC saltand lubricant, as described herein, and in certain such embodiments, theimmediate release formulations are substantially free of otherexcipients or adjuvants. In other embodiments, the immediate releaseformulations described herein include a combination of the APC salt,lubricant, and binder, as described herein, and in certain suchembodiments, the immediate release formulations are substantially freeof other excipients or adjuvants. Though the immediate releaseformulations described herein may be formulated using a combination ofdrug and one or more of a lubricant and binder, in certain embodiments,the compositions described herein may include one or more additionalexcipients selected from, for example, fillers, compression aids,diluents, disintegrants, colorants, flavorants, buffering agents,coatings, glidants, or other suitable excipients.

The immediate release formulations described herein may be manufacturedusing standard techniques, such as wet granulation, roller compaction,fluid bed granulation, and dry powder blending. Suitable methods for themanufacture of the immediate release formulations and unit dosage formsdescribed herein are provided, for example, in Remington, 20^(th)edition, Chapter 45 (Oral Solid Dosage Forms). It has been found that,even without the aid of binders or non-lubricating excipients, such ascompression aids, wet granulation techniques can afford flowablegranules with compression characteristics suitable for forming unitdosage forms as described herein. Therefore, in certain embodiments,where a drug content greater than about 85%, 90% or 95% by weight isdesired for the immediate release formulation, wet granulationtechniques may be used to prepare immediate release formulations asdescribed herein. In such embodiments, as illustrated in the Examplesprovided herein, conventional organic or aqueous solvents may be used inthe wet granulation process. Suitable wet granulation processes can beperformed as fluidized bed, high shear, or low shear (wet massing)granulation techniques, as are known in the art.

In addition to one or more the APC salt, lubricant, and binder, wheredesired, the immediate release formulations described herein may alsoinclude fillers or compression aids selected from at least one oflactose, calcium carbonate, calcium sulfate, compressible sugars,dextrates, dextrin, dextrose, kaolin, magnesium carbonate, magnesiumoxide, maltodextrin, mannitol, microcrystalline cellulose, powderedcellulose, and sucrose. Where a filler or compression aid is used, incertain embodiments, it may be included in the immediate releaseformulation in an amount ranging from about 1%-15% by weight.

Where desired or necessary, the outer surface of an immediate releasedosage form as disclosed herein may be coated with a moisture barrierlayer using materials and methods known in the art. For example, wherethe APC salt delivered by the unit dosage form is highly hygroscopic,providing a moisture barrier layer over the immediate release dosageform as disclosed herein may be desirable. For example, protection of animmediate release dosage form as disclosed herein from water duringstorage may be provided or enhanced by coating the tablet with a coatingof a substantially water soluble or insoluble polymer. Usefulwater-insoluble or water-resistant coating polymers include ethylcellulose and polyvinyl acetates. Further water-insoluble or waterresistant coating polymers include polyacrylates, polymethacrylates orthe like. Suitable water-soluble polymers include polyvinyl alcohol andHPMC. Further suitable water-soluble polymers include PVP, HPC, HPEC,PEG, HEC and the like.

Where desired or necessary, the outer surface of an immediate releasedosage form as disclosed herein may be coated with a color overcoat orother aesthetic or functional layer using materials and methods known inthe art.

The dosage forms disclosed herein can also be provided as a kitcomprising, separately packaged, a container comprising a plurality ofimmediate release tablets, which tablets can be individually packaged,as in foil envelopes or in a blister pack. The tablets can be packagedin many conformations with or without desiccants or other materials toprevent ingress of water. Instruction materials or means, such asprinted labeling, can also be included for their administration, e.g.,sequentially over a preselected time period and/or at preselectedintervals, to yield the desired levels of APC in vivo for preselectedperiods of time, to treat a preselected condition.

Daily Dosage and Treatment Regimens

In the methods described herein, the typical daily dose of the APC saltfor subjects with normal renal function, equivalent to 75-150 mg of APC,is modified for certain renally impaired subjects. As discussed above,for a subject with an eGFR of 30-59 ml/min/1.73 m², i.e., a subject withmoderate renal impairment, the APC salt is administered once daily at aninitial dose equivalent to 37.5 mg of APC. In some cases, this dailydose may be increased after at least 7 days of the initial doseequivalent to 75 mg of APC. Further, in some embodiments, for a subjectwith an eGFR of 15-29 ml/min/1.73 m², i.e., a subject with severe renalimpairment, the APC salt is administered once daily at a maximum doseequivalent to 37.5 of APC. In some embodiments, such dosages may be usedfor a subject who has narcolepsy, a subject with OSA, or when reductionof toxicity of the APC salt is indicated. In particular embodiments, theAPC salt is APC-HCl.

A dose is “equivalent to” a 37.5 mg or 75 mg of APC, if the weight ofthe APC base (the “active moiety”) in the formulation is 37.5 mg or 75mg, respectively, regardless of the weight of the APC salt. Thus, theweight of the APC salt may be greater than 37.5 mg or 75 mg,respectively, in the formulation. Where APC is provided in the form ofAPC-HCl salt, a dose of 37.5 mg APC is equivalent to 44.7 mg (or 44.65mg) of APC-HCl; a dose of 75 mg APC is equivalent to 89.3 mg of APC-HCl;and a dose of 150 mg APC is equivalent to 178.5 mg of APC-HCl. An“initial dose equivalent” is the daily dose at which the subject startsthe treatment regimen, corresponding to the weight of the active moiety(APC), and the initial dose may be increased at some time point, such asin a number of days (e.g., 1, 2, 3, 4, 5, 6, 7, or more days). The“maximum dose equivalent” is the largest dose, corresponding to theweight of the active moiety (APC), that the patient may be administereddaily at any time point.

In general, the daily dose is administered once daily. However, in someembodiments, the daily dose may be administered at two or more differenttime points. Administration of the APC salt can continue for one, two,three, four, five, six, seven, eight, nine, ten, eleven, or twelve weeksor longer. Alternatively, administration of the APC salt can continuefor one, two, or three months, or longer. Optionally, after a period ofrest, the compound can be administered under the same or a differentschedule. The period of rest can be one, two, three, or four weeks, orlonger, according to the pharmacodynamic effects of the compound on thesubject. In another embodiment, the compound can be administered tobuild up to a certain level, then maintained at a constant level andthen a tailing dosage.

In one aspect of the invention, the APC salt is delivered to a subjectconcurrently with an additional therapeutic agent. The additionaltherapeutic agent can be delivered in the same composition as thecompound or in a separate composition. The additional therapeutic agentcan be delivered to the subject on a different schedule or by adifferent route as compared to the compound. The additional therapeuticagent can be any agent that provides a benefit to the subject. Suchagents include, without limitation, stimulants, anti-psychotics,anti-depressants, agents for neurological disorders, andchemotherapeutic agents. In some embodiments, the APC salt is deliveredto a subject concurrently with an additional therapeutic agent that isnot a monoamine oxidase inhibitor. In still other embodiments, the APCsalt is delivered to a subject who has not been treated with a monoamineoxidase inhibitor within the preceding 14 days. In exemplary embodimentsof the invention, a subject with obstructive sleep apnea is treated withAPC concurrently with adherence to a primary OSA therapy. Examples ofprimary OSA therapies include, without limitation, positive airwaypressure (PAP), continuous positive airway pressure (CPAP), oralappliances, and surgical procedures. One therapeutic agent that can beadministered during the same period is Xyrem®, sold commercially by JazzPharmaceuticals, which is used to treat narcolepsy and cataplexy. SeeU.S. Pat. Nos. 8,952,062 and 9,050,302.

The APC salt can be administered at any time during the day, but in someembodiments, the APC salt is administered to the subject no later thanat least 12 hours before the bedtime of the subject. Studies by thepresent inventors have found that that administration of the APC saltwithin a few of hours of waking minimizes side effects of the treatmentsuch as insomnia. In some embodiments, the APC is administered shortlyafter waking, e.g., within about 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, or 3hours of waking. In exemplary embodiments, the APC is administered atleast 9 hours before the bedtime of the subject, e.g., at least 9, 10,11, 12, 13, 14, 15, or 16 or more hours before bedtime.

Subjects

The present invention finds use in research as well as veterinary andmedical applications. Suitable subjects are generally mammaliansubjects. The term “mammal” as used herein includes, but is not limitedto, humans, non-human primates, cattle, sheep, goats, pigs, horses,cats, dog, rabbits, rodents (e.g., rats or mice), etc. Human subjectsinclude neonates, infants, juveniles, adults and geriatric subjects. Insome embodiments of the invention, the human subject is an adult.

In particular embodiments, the subject is a human subject that hasexcessive daytime sleepiness or another disorder amenable to treatmentwith the APC salt. In other embodiments, the subject used in the methodsof the invention is an animal model of excessive daytime sleepiness oranother disorder amenable to treatment with APC.

The subject can be a subject “in need of” the methods of the presentinvention, e.g., in need of the therapeutic effects of the inventivemethods. For example, the subject can be a subject that is experiencingexcessive daytime sleepiness or another disorder or condition amenableto treatment with APC, is suspected of having excessive daytimesleepiness or another disorder or condition amenable to treatment withAPC, and/or is anticipated to experience excessive daytime sleepiness oranother disorder or condition amenable to treatment with APC, and themethods and compositions of the invention are used for therapeuticand/or prophylactic treatment. Disorders amenable to treatment with APCinclude, without limitation, sleep-wake disorder, excessive daytimesleepiness, depression, attention deficit/hyperactivity disorder, drugaddiction, bipolar disorder, fibromyalgia, fatigue, obesity, restlesslegs syndrome, cataplexy, and sexual dysfunction.

Specific embodiments of the invention include, without limitation, thefollowing.

Embodiment 1

A method of providing [R]-2-amino-3-phenylpropylcarbamate hydrochloride(APC-HCl) to a renally impaired subject in need thereof according to adose escalation regimen, said method comprising

providing to the subject a first oral daily dose equivalent to 37.5 mg[R]-2-amino-3-phenylpropylcarbamate (APC) from day one to day n₁ of thedose escalation regimen; and

providing to the subject a second oral daily dose equivalent to 75 mgAPC starting on day n₂ of the dose escalation regimen,

wherein n₁ is an integer equal to or greater than 5 and n₂ is equal tothe sum of n₁+1,

wherein the renally impaired subject is not provided a daily doseexceeding a dose equivalent to 75 mg APC, and

wherein the renally impaired subject has an estimated glomerularfiltration rate (eGFR) of about 30 mL/min/1.73 m² to about 59mL/min/1.73 m².

Embodiment 2

The method of embodiment 1, wherein the subject is provided APC-HCl forthe treatment of excessive daytime sleepiness.

Embodiment 3

The method of embodiment 2, wherein the excessive daytime sleepiness isassociated with narcolepsy.

Embodiment 4

The method of embodiment 2, wherein the excessive daytime sleepiness isassociated with obstructive sleep apnea.

Embodiment 5

The method of embodiment 1, wherein the subject is provided the firstoral daily dose in the form of about 44.7 mg APC-HCl.

Embodiment 6

The method of embodiment 1, wherein the subject is provided the secondoral daily dose in the form of about 89.3 mg APC-HCl.

Embodiment 7

The method of embodiment 1, wherein the subject is provided a first oraldaily dose in the form of about 44.7 mg APC-HCl and a second oral dailydose in the form of about 89.3 mg APC-HCl.

Embodiment 8

The method of embodiment 1, wherein the first oral daily dose and secondoral daily dose are each administered upon the subject's awakening.

Embodiment 9

The method of embodiment 1, wherein the first oral daily dose and secondoral daily dose are each administered more than nine hours in advance ofthe subject's bedtime.

Embodiment 10

The method of embodiment 1, wherein the subject is a human.

Embodiment 11

The method of embodiment 1, wherein the eGFR is determined using theModification in Diet in Renal Disease equation.

Embodiment 12

The method of embodiment 1, wherein n₁ is an integer equal to or greaterthan 7.

Embodiment 13

A method of providing APC-HCl to a renally impaired subject withnarcolepsy in need thereof, said method comprising:

providing to the subject an oral daily dose equivalent to 37.5 mg APC,

wherein the renally impaired subject is not provided a daily doseexceeding a dose equivalent to 37.5 mg APC; and

wherein the renally impaired subject has an eGFR of about 15 ml/min/1.73m² to about 29 ml/min/1.73 m².

Embodiment 14

The method of embodiment 13, wherein the oral daily dose is provided tothe renally impaired subject in the form of 44.7 mg APC-HCl.

Embodiment 15

The method of embodiment 13, wherein the oral daily dose is administeredupon the subject's awakening.

Embodiment 16

The method of embodiment 13, wherein the oral daily dose is administeredmore than nine hours in advance of the subject's bedtime.

Embodiment 17

The method of embodiment 13, wherein the subject is a human.

Embodiment 18

The method of embodiment 17, wherein the subject is an adult.

Embodiment 19

The method of embodiment 13, wherein the eGFR is determined using theModification in Diet in Renal Disease equation.

Embodiment 20

A method of treating excessive daytime sleepiness in a renally impairedsubject with narcolepsy in need thereof, comprising administering to thesubject APC-HCl at an initial dose equivalent to 37.5 mg APC once daily;

wherein the subject has an eGFR of 30-59 ml/min/1.73 m²; therebytreating excessive daytime sleepiness in the subject.

Embodiment 21

The method of embodiment 20, further comprising increasing the dose to amaximum equivalent to 75 APC once daily after at least 5 days.

Embodiment 22

The method of embodiment 21, wherein the dose is increased to a maximumequivalent to 75 mg APC once daily after at least 7 days.

Embodiment 23

A method of treating excessive daytime sleepiness in a renally impairedsubject with narcolepsy in need thereof, comprising administering to thesubject APC-HCl at a maximum dose equivalent to 37.5 mg APC once daily;

wherein the subject has an eGFR of 15-29 ml/min/1.73 m²; therebytreating excessive daytime sleepiness in the subject.

Embodiment 24

A method of guiding APC therapy in a renally impaired subject withnarcolepsy in need thereof, comprising

a. determining if the subject has mild renal impairment (an eGFR of60-89 ml/min/1.73 m²), moderate renal impairment (an eGFR of 30-59ml/min/1.73 m²), severe renal impairment (an eGFR of 15-29 ml/min/1.73m²), or end stage renal disease (an eGFRof less than 15 ml/min/1.73 m²);andb. administering to the subject APC-HCl according to a regimenrecommended for subjects without renal impairment if the subject hasmild renal impairment, said regimen comprising an initial doseequivalent to 75 mg APC once daily and a maximum dose equivalent to 150mg APC once daily;or administering to the subject APC-HCl at an initial dose equivalent to37.5 mg APC once daily and a maximum dose equivalent to 75 mg APC oncedaily if the subject has moderate renal impairment; or administering tothe subject APC-HCl at a maximum dose equivalent to 37.5 mg APC oncedaily if the subject has severe renal impairment; ornot administering to the subject APC-HCl if the subject has end stagerenal disease.

Embodiment 25

The method of embodiment 24, further comprising measuring the eGFR inthe subject prior to step a.

Embodiment 26

The method of embodiment 24, wherein the dose is increased from a doseequivalent to 75 mg APC to a dose equivalent to 150 mg APC after atleast 3 days if the subject has mild renal impairment and the dose isincreased from a dose equivalent to 37.5 mg APC to a dose equivalent to75 mg APC after at least 7 days if the subject has moderate renalimpairment.

Embodiment 27

A method of guiding APC therapy in a renally impaired subject withobstructive sleep apnea in need thereof, comprising:

a. determining if the subject has mild renal impairment (an eGFR of60-89 ml/min/1.73 m²), moderate renal impairment (an eGFR of 30-59ml/min/1.73 m²), severe renal impairment (an eGFR of 15-29 ml/min/1.73m²), or end stage renal disease (an eGFR of less than 15 ml/min/1.73m²); andb. administering to the subject APC-HCl according to a regimenrecommended for subjects without renal impairment if the subject hasmild renal impairment, said regimen comprising an initial doseequivalent to 37.5 mg APC once daily and a maximum dose equivalent to150 mg APC once daily;or administering to the subject APC-HCl at an initial dose equivalent to37.5 mg APC once daily and a maximum dose equivalent to 75 mg APC oncedaily if the subject has moderate renal impairment; oradministering to the subject APC-HCl at a maximum dose equivalent to37.5 mg APC once daily if the subject has severe renal impairment; ornot administering to the subject APC-HCl if the subject has end stagerenal disease.

Embodiment 28

The method of embodiment 27, further comprising measuring the eGFR inthe subject prior to step a.

Embodiment 29

The method of embodiment 27, wherein the regimen comprises doubling thedose of APC-HCl at intervals of at least 3 days if the subject has mildrenal impairment and increasing the dose from a dose equivalent to 37.5mg APC to a dose equivalent to 75 mg APC after at least 7 days if thesubject has moderate renal impairment.

Embodiment 30

A method of treating excessive daytime sleepiness in a renally impairedsubject with obstructive sleep apnea in need thereof, comprisingadministering to the subject APC-HCl at an initial dose equivalent to37.5 mg APC once daily, wherein the subject has an eGFR of 30-59ml/min/1.73 m², thereby treating excessive daytime sleepiness in thesubject.

Embodiment 31

The method of embodiment 30, wherein the dose is increased to a maximumequivalent to 75 mg APC once daily after at least 7 days.

Embodiment 32

A method of treating excessive daytime sleepiness in a renally impairedsubject with obstructive sleep apnea in need thereof, comprisingadministering to the subject APC-HCl at a maximum dose equivalent to37.5 mg APC once daily;

wherein the subject has an eGFR of 15-29 ml/min/1.73 m², therebytreating excessive daytime sleepiness in the subject.

Embodiment 33

A method of reducing toxicity of APC-HCl therapy in a renally impairedsubject, comprising:

administering to the subject APC-HCl at an initial dose equivalent to37.5 mg APC once daily;

increasing the daily dose to a maximum dose equivalent to 75 mg APCafter at least 7 days;

wherein the subject has an eGFR of 30-59 ml/min/1.73 m², therebyreducing toxicity of APC-HCl therapy in the subject.

Embodiment 34

The method of embodiment 33, wherein the initial dose is provided in theform of about 44.7 mg APC-HCl and the maximum dose is provided in theform of about 89.3 mg APC-HCl.

Embodiment 35

A method of reducing toxicity of APC-HCl therapy in a renally impairedsubject, comprising administering to the subject APC-HCl at a maximumdose equivalent to 37.5 mg APC once daily;

wherein the subject has an eGFR of 15-29 ml/min/1.73 m², therebyreducing toxicity of APC-HCl in the subject.

Embodiment 36

The method of embodiment 35, wherein the maximum dose is provided in theform of about 44.7 mg APC-HCl.

Embodiment 37

A method of reducing toxicity of APC-HCl therapy in a renally impairedsubject, comprising:

a. determining if the subject has mild renal impairment (an eGFR of60-89 ml/min/1.73 m²), moderate renal impairment (an eGFR of 30-59ml/min/1.73 m²), severe renal impairment (an eGFR of 15-29 ml/min/1.73m²), or end stage renal disease (an eGFR of <15 ml/min/1.73 m²); andb. administering to the subject APC-HCl at a dose of APC-HCl recommendedfor subjects without renal impairment if the subject has mild renalimpairment, wherein the dose of APC-HCl recommended for subjects withoutrenal impairment comprises an initial dose equivalent to 75 mg APC oncedaily and a maximum dose equivalent to 150 mg APC once daily after atleast 3 days; oradministering to the subject APC-HCl at an initial dose equivalent to37.5 mg APC once daily and a maximum dose equivalent to 75 mg APC oncedaily after at least 7 days if the subject has moderate renalimpairment; oradministering to the subject APC-HCl at a maximum dose equivalent to37.5 mg APC1 once daily if the subject has severe renal impairment; ornot administering to the subject APC-HCl if the subject has end stagerenal disease.

Embodiment 38

The method of embodiment 37, further comprising measuring the eGFR inthe subject prior to step a.

Embodiment 39

The method of embodiment 37, wherein the eGFR is calculated by theModification of Diet in Renal Disease equation.

Embodiment 40

The method of embodiment 37, wherein the subject is a human.

Embodiment 41

The method of embodiment 40, wherein the subject is an adult.

Embodiment 42

The method of embodiment 37, wherein the APC-HCl is administered orally.

Embodiment 43

The method of embodiment 37, wherein the APC-HCl is formulated with apharmaceutical carrier.

Embodiment 44

The method of embodiment 37, wherein the subject is being treated forexcessive daytime sleepiness associated with narcolepsy.

The present invention is explained in greater detail in the followingnon-limiting Examples. Each example has a self-contained list ofreferences.

Example 1: Evaluation of the PK of Solriamfetol HCl in Participants withRenal Impairment and Those with ESRD Undergoing Hemodialysis Comparedwith Healthy Participants with Normal Renal Function

Methods

In healthy subjects with normal renal function, solriamfetol HCl isrenally excreted ˜90% unchanged within 48 hours of administration. Thus,renal impairment, as well as hemodialysis in individuals with end-stagerenal disease (ESRD), could affect the PK of solriamfetol HCl. Toascertain the precise impact of renal impairment and hemodialysis onpharmacokinetics and safety of solriamfetol HCl, a Phase 1,parallel-group, open-label, single-dose study was conducted at 2 U.S.sites. The protocol was approved by the IntegReview Institutional ReviewBoard (Austin, Tex.), and the study was conducted in compliance with theprotocol, the Guideline for Good Clinical Practice E6; the US Code ofFederal Regulations pertaining to conduct and reporting of clinicalstudies; the Clinical Trials Directive of the European Medicines Agency(Directive 2001/20/EC); and the Declaration of Helsinki. Writteninformed consent was obtained from each subject before enrollment in thestudy and before performance of any study-related procedure. See, also,Zomorodi K, Chen D, Lee L, Lasseter K, Marbury T. An Open-Label,Single-Dose, Phase 1 Study of the Pharmacokinetics and Safety of JZP-110in Subjects With Normal or Impaired Renal Function and With End-StageRenal Disease Requiring Hemodialysis [abstract]. Sleep. 2017; 40(suppl): A382-383.

Eligible participants were men and non-pregnant, non-lactating womenbetween the ages of 18 and 80 years, with a body mass index (BMI)≤35kg/m². Women of childbearing potential were required to have used amedically accepted method of birth control for at least 2 months priorto the first dose of study drug, with continued use throughout the studyperiod and for 30 days after study completion. Participants wereexcluded if they had a clinically significant medical abnormality (otherthan renal impairment or its underlying causes), or any unstableconditions including neurological or psychiatric disorder, hepatic,endocrine, cardiovascular, gastrointestinal, pulmonary, or metabolicdisease, or any other abnormality that could interfere with the PKevaluation of the study drug or the participant's completion of thetrial.

Eligible participants were assigned to 1 of 5 groups according to renaldisease status as measured by the estimated glomerular filtration rate(eGFR) on the day prior to dosing, calculated using the Modification inDiet in Renal Disease equation. Group 1 consisted of healthyparticipants with normal renal function (eGFR≥90 mL/min/1.73 m²) andserved as the control group. Groups 2, 3, and 4 had mild, moderate, andsevere renal impairment based on eGFRs of 60-89, 30-59, and <30mL/min/1.73 m², respectively. Group 5 consisted of participants withESRD who required ≥3 hemodialysis treatments per week for the preceding3 months. Every effort was made to ensure that the groups werecomparable with respect to age, sex, and body mass index (BMI). Group 1was enrolled last to facilitate matching the mean age, BMI, and sexdistribution of Groups 2-5.

Among participants with impaired renal function, continued use ofmedications necessary for treatment of renal function and/or coexistingdisease was allowed, with the exception of monoamine oxidase inhibitorsand medications with known risk for torsade de pointes.

Groups 1-4 received one dose of solriamfetol HCl (89.3 mg; equivalent to75-mg solriamfetol) on day 1; Group 5 received one dose equivalent to75-mg dose on day 1 followed by 4-hour hemodialysis (designated Group5.2), and one dose equivalent to 75-mg solriamfetol on day 8 withouthemodialysis (designated Group 5.1). All doses were administered on anempty stomach following an overnight fast except for participants inGroup 5, who received a standardized snack on day 7 and breakfast earlyon day 8 before starting an 8-hour fast. Participants remained fastingfor 4 hours after administration, with water allowed except for 1 hourbefore and after dosing.

In this study, 75 mg solriamfetol was selected as the dose foradministration in participants with renal impairment as it wasconsidered sufficiently low and potentially safe for this population.The 75-mg dose was expected to result in plasma concentrations ofsolriamfetol that were above the assay detection level at time pointssufficient to characterize the PK profile.

Serial blood samples of approximately 4 mL were collected within 30minutes prior to dosing and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12,24, 36, and 48 hours post-dose in Groups 1-3, with continued sampling at60 and 72 hours post-dose in Groups 4 and 5. All blood samples werecollected into labeled K₂EDTA tubes by direct venipuncture or indwellingcatheter and kept on ice until the samples were centrifuged within 30minutes of collection at approximately 2500 rpm (1315×g) at 4° C. for 10minutes. The plasma was transferred into polypropylene tubes forfreezing and storage at −70° C. until analysis.

Urine samples were collected predose and for the time intervals of 0-4,4-8, 8-12, 12-24, and 24-48 hours in Groups 1-3, with additionalcollection for the 48-72 hour time interval in Groups 4 and 5. Duringthe hemodialysis period on day 1 for Group 5, dialysate samples and pre-and post-dialyzer paired blood samples were collected at pre-dialysis (2hours), and at 3, 4, 5, and 6 hours following dosing. Urine anddialysate samples were aliquoted into polypropylene tubes for freezingand storage at −70° C. until analysis. All blood, urine, and dialysatesamples were shipped on dry ice to a central bioanalytical laboratory.

Bioanalytical analyses were performed by a central laboratory (KCAS,LLC, Shawnee, Kans.) using validated proprietary methods that includedextraction/derivatization and liquid chromatography-tandem massspectrometry (LC-MS/MS). Measurement of solriamfetol was over the linearrange of 8.42 to 4,210 ng/mL in plasma, 0.21 to 84.2 μg/mL in urine, and1.68 to 842 ng/mL in dialysate. Solriamfetol was removed from dialysatesamples with use of the Fresenius Optiflux F180NR dialyzer (FreseniusMedical Care, Waltham, Mass.). Assay performance was monitored byspiking blank interference free human plasma with positive controls andinternal standards to generate standard curve and quality controlsamples. After derivatization, samples were chromatographed on a C8reversed phase analytical HPLC (high-performance liquid chromatography)column, with subsequent monitoring using an API4000 LC-MS/MS unit(Sciex, Framingham, Mass.). Quantification was based on setting acalibration graph using the internal standard method. Coefficients ofvariation (CVs) for quality control samples were 3.2% to 6.0% for theplasma samples, 1.6% to 5.6% for the urine samples, and 3.5% to 7.1% forthe dialysate samples.

The following plasma PK parameters were evaluated usingnon-compartmental analysis in Phoenix® WinNonlin® Version 6.3: C_(max);time to reach C_(max) following drug administration (t_(max)); t_(1/2);area under the plasma concentration-time curve from time zero to time oflast quantifiable concentration (AUC_(t)); AUC from time zero toinfinity (AUC_(∞)); apparent total clearance of the drug from plasmaafter oral administration (CL/F); and apparent volume of distribution(V_(d)/F). The PK parameters for solriamfetol in urine included theamount of unchanged drug excreted in urine (A_(e)) over 48 or 72 hours;the fraction of the dose excreted unchanged in urine (F_(e)); and renalclearance of the drug (CL_(R)). For participants on hemodialysis (Group5), the additional PK parameters included the amount of solriamfetolcleared by the 4-hour hemodialysis (A_(dial)); the fraction of doseremoved by the 4-hour hemodialysis (F_(dial)); and hemodialysisclearance (CL_(dial)) calculated as CL_(dial)=A_(dial)/AUC_(dial) whereAUC_(dial) is the area under the pre-dialyzer plasma concentration-timecurve during the hemodialysis period.

PK parameters were summarized by group using descriptive statistics. Toassess differences in PK between each level of renal impairment (Groups2-5) versus participants with normal renal function (Group 1), a lineareffects model was used to compare natural log-transformed PK parameters(C_(max), AUC_(t), and AUC_(∞)). For Group 5, the participants withoutdialysis on day 8 (Group 5.1) and the participants who received dialysison day 1 (Group 5.2) were analyzed and compared separately.

Point estimates and 90% confidence intervals (CIs) for differences onthe natural log scale were exponentiated to obtain estimates for ratiosof geometric means on the original scale. The 90% CIs around thegeometric means ratios were presented for each pairwise comparison andexpressed as a percentage relative to the geometric means of thereference group (Group 1). The inter-participant CV was estimated. Toevaluate effects of dialysis on PK parameters for Group 5, an analysisof variance model was used that included “Day” as a fixed effect andmeasurements within the participant as a repeated measure. Day 8 wasused as the reference for comparison. In addition, nonparametricanalysis was conducted for t_(max) as appropriate.

All statistical analyses were conducted using SAS version 9.3 (SASInstitute, Cary, N.C.).

Results

Of the 31 participants who were enrolled and received treatment (6participants in each of Groups 1 through 4 and 7 participants in Group5), 30 participants (97%) completed the study. One participant fromGroup 5 discontinued due to adverse events. Participant demographics(Table 1) show that most participants in Groups 1-4 were white; however,most participants in Group 5 were black. There were at least 2participants per sex in each group, and mean age for Groups 1, 2, 3, and4 were comparable with an overlap in the range; the age range in Group 5was lower than in the other groups. Mean BMI for Groups 1, 2, 3, 4, and5 were comparable, with an overlap in the range. Furthermore, allparticipants in Group 1 matched the mean age (±10 years) and BMI (±20%)of participants in Groups 2-5.

TABLE 1 Demographic Characteristics of the Study Population Group 1Group 5 Normal Group 2 Group 3 Group 4 End-stage renal Mild renalModerate renal Severe renal renal function impairment impairmentimpairment disease Variable (n = 6) (n = 6) (n = 6) (n = 6) (n = 7) Sex,n (%) Female 3 (50) 4 (67) 2 (33) 2 (33) 2 (29) Male 3 (50) 2 (33) 4(67) 4 (67) 5 (71) Race, n (%) White 5 (83) 5 (83) 4 (67) 5 (83) 1 (14)Black 1(17) 1(17) 2 (33) 1(17) 6 (86) Ethnicity, n (%) Non- Hispanic or0 3 (50) 2 (33) 3 (50) 6 (86) Latino Hispanic or Latino 6 (100) 3 (50) 4(67) 3 (50) 1 (14) Age, 55.8 (3.9) 67.8 (7.4) 70.2 (7.7) 59.7 (15.6)42.0 (7.6) mean (SD), y Weight, mean 73.1 (6.8) 67.1 (14.2) 76.8 (11.5)85.5 (16.4) 88.2 (10.5) (SD), kg BMI, mean (SD), 28.1 (2.7) 25.1 (4.1)28.8 (1.9) 29.3 (3.0) 29.9 (3.0) kg/m2 eGFR, mean (SD), 111.8 (32.3)78.5 (8.4) 44.2 (6.2) 16.2 (5.8) 7.4 (4.8) mL/min/1.73 m2 BMI = bodymass index

For all study groups, mean PK parameters are summarized in Table 2 andmean plasma solriamfetol concentration-time profiles are shown in FIGS.1A and 1B.

TABLE 2 Solriamfetol Pharmacokinetic Parameters by Level of RenalFunction Mean ± standard deviation (% coefficient of variation)End-stage renal disease (Group 5) Normal renal Renal impairment Group5.1 Group 5.2 function Group 2 Group 3 Group 4 Without With Group 1 MildModerate Severe hemodialysis^(a) hemodialysis Variable (n = 6) (n = 6)(n = 6) (n = 6) (n = 6) (n = 7)^(b) C_(max), 499.0 ± 142.4 521.8 ± 118.8517.3 ± 131.6 552.8 ± 154.4 474.1 ± 79.0 396.4 ± 75.4 ng/mL (28.5)(22.8) (25.4) (27.9) (16.7) (19.0) t_(max),^(c) h 1.3 1.5 1.5 2.0 3.31.5 (0.5, 2.0) (0.5, 2.0) (1.0, 2.5) (0.5, 3.0) (1.0, 24.0) (1.5, 10.0)t_(1/2), h 7.6 ± 5.1 9.1 ± 1.6 14.3 ± 4.5 29.6 ± 14.4 100.5 ± 78.8 164.7± 81.4 (67.7) (18.1) (31.4) (48.7) (78.4)^(d) (49.4)^(e) AUC_(t), 4849 ±3454 6613 ± 1574 9230 ± 2538 17500 ± 9267 25580 ± 4544 18920 ± 3131 ng ·h/mL^(f) (71.2) (23.8) (27.5) (52.9) (17.8) (16.5) AUC_(∞), 5273 ± 41046836 ± 1730 10470 ± 3642 23650 ± 16776 64560 ± 35962 76770 ± 41993 ng ·h/mL (77.8) (25.3) (34.8) (70.9) (55.7)^(d) (54.7)^(e) CL/F, L/h 19.8 ±10.1 11.5 ± 2.5 7.8 ± 2.4 4.7 ± 2.8 1.6 ± 1.1 1.5 ± 1.3 (50.9) (22.1)(30.5) (59.4) (72.3)^(d) (91.0)^(e) V_(d)/F, L 163.9 ± 23.8  147.2 ±29.1 152.0 ± 32.6  157.2 ± 41.2  153.6 ± 45.6  231.4 ± 28.5  (14.5)(19.8) (21.4) (26.2) (29.7)^(d) (12.3)^(e) ^(a)Baseline adjusted toremove the impact of the day 1 dose on the day 8 concentration profile.^(b)Excluding 2 concentration values: 1 participant at predose, and 1participant at 24 hours. ^(c)For t_(max), median (min, max) ispresented. ^(d)n = 3. ^(e)n = 6. ^(f)Over 48 h for normal, mild, andmoderate, and over 72 h for severe.

In general, mean C_(max) and t_(max) were not substantially affected byrenal impairment across Groups 1-4 (Table 2). However, solriamfetol AUCand t_(1/2) values increased with increasing levels of renal impairment.Solriamfetol mean±SD overall exposure (AUC_(∞)) increased from 5273±4104ng·h/mL in participants with normal renal function to 6836 ng·h/mL±1730in Group 2 (mild impairment), 10,470±3642 in Group 3 (moderateimpairment), and 23,650±16,776 in Group 4 (severe impairment) (Table 2).Similarly, solriamfetol mean±SD t_(1/2) was 7.6±5.1 hours inparticipants with normal renal function and increased with greaterlevels of renal impairment: 9.1±1.6, 14.3±4.5, and 29.6±14.4 hours inGroups 2, 3, and 4, respectively (Table 2). While CL/F decreased withgreater levels of renal impairment, there were no substantial changes inV_(d)/F (Table 2). A plot of solriamfetol CL/F versus day −1 eGFR forGroups 1-4 is presented in FIG. 2. This relationship is best describedby the equation: solriamfetol CL/F (L/h)=0.63184+0.16463×eGFR(mL/min/1.73 m²).

Among participants with ESRD (Group 5), overall exposure (AUC_(t)) wasapproximately 5-fold higher for participants without dialysis on day 8(Group 5.1; 25 580±4544 ng·h/mL) and about 4-fold higher amongparticipants with dialysis on day 1 (Group 5.2; 18 920±3131) relative toGroup 1 (4849±3454) (Table 2). Mean t_(1/2) values exceeded 100 hours inboth Group 5.1 (100.5 hours) and Group 5.2 (164.7 hours) (Table 2), andcompared with Group 1, C_(max) values were slightly lower and t_(max)values differed significantly (P≤0.05 for both).

Ratios of geometric means and their associated 90% CIs for the pairwisecomparisons of solriamfetol plasma PK parameters for Groups 2 through 5versus Group 1 are presented in Table 3.

TABLE 3 Comparisons of Solriamfetol Plasma PK Parameters Group 5.1 Group5.2 Group 1 Group 2 Group 3 Group 4 Without With PK Normal Mild ModerateSevere hemodialysis hemodialysis parameter (n = 6) (n = 6) (n = 6) (n =6) (n = 6) (n = 7)^(a) Geometric LS mean Cmax, 482.3 510.5 503.2 533.0468.8 389.9 ng/mL AUCt, 4087.3 6469.6 8960.2 15 549 25 253 18 689 ng ·h/mL^(b) AUC∞), 4363.9 6672.4 10002 19 140 56 319^(c) 65 306^(d) ng ·h/mL Percent ratio (90% confidence interval) of geometric mean relativeto Group 1 Cmax — 105.9 104.3 110.5 97.2 80.9 (80.6, (78.4, (81.1,(76.1, (63.4, 139.0) 138.9) 150.6) 124.1) 103.1) AUCt — 158.3 219.2380.4 617.8 457.2 (97.5, (133.7, (208.4, (385.3, (296.6, 256.9) 359.6)694.4) 990.8) 704.9) AUC∞ — 152.9 229.2 438.6 1290.6 1496.5 (92.9,(135.6, (217.3, (542.78, (748.7, 251.7) 387.4) 885.3) 3068.5) 2991.2)Notes: Parameters were In-transformed prior to analysis. Geometricleast-squares means (LSMs) are calculated by exponentiating the LSMsfrom the analysis of variance. % mean ratio = 100 * (test/reference).^(a)Excluding 2 concentration values: 1 participant at predose, and 1participant at 24 hours. ^(b)Over 48 hours for Groups 1-3 and over 72hours for Groups 4 and 5. ^(c)n = 3. ^(d)n = 6.

As shown, small increases were observed in C_(max), which wasapproximately 6%, 4%, and 11% higher in Groups 2, 3, and 4,respectively, versus Group 1. However, total solriamfetol exposure(AUC_(∞)) in Groups 2, 3, and 4 was 53%, 129%, and 339% higher,respectively, relative to Group 1. In participants with ESRD, C_(max)was approximately 3% and 19% lower in groups 5.1 (ESRD withouthemodialysis) and 5.2 (ESRD with hemodialysis), respectively, versusGroup 1, and exposure was approximately 518% and 357% higher in the 2groups versus Group 1.

Renal clearance (CL_(R)) and the cumulative amount of solriamfetolexcreted in urine decreased as renal impairment increased (Table 4).

TABLE 4 Urinary Excretion of Solriamfetol Mean ± standard deviation (%coefficient of variation) Group 1 Normal renal Group 2 Group 3 Group 4PK function Mild Moderate Severe parameter (n = 6) (n = 6) (n = 6) (n =6) F_(e(0-48)), 85.8 ± 7.7 80.0 ± 9.0 66.4 ± 12.8 57.1 ± 18.6 % (9.0)(11.2) (19.2) (32.5) CL_(R), L/h 17.0 ± 7.7 9.3 ± 1.6 5.8 ± 2.0 3.8 ±2.6 (45.4) (17.1) (34.1) (68.0) CL_(R), renal clearance; F_(e(0-48)),fraction of the dose excreted unchanged in urine in 48 hours.

In Group 1, the mean±SD percentage of solriamfetol recovered unchangedin urine over 48 hours was 85.8%±7.7% and decreased to 80.0%±9.0%,66.4%±12.8%, and 57.1%±18.6% in Groups 2, 3, and 4, respectively. Meansolriamfetol renal clearance also decreased with renal impairment, from17.0±7.7 L/h in the normal renal function group to 9.3±1.6 L/h in Group2, 5.8±2.0 L/h in Group 3, and 3.8±2.6 L/h in Group 4. Only 1participant made urine and was able to provide data in Group 5, and thecumulative amount of solriamfetol excreted in urine was lower withhemodialysis, 42.1%, compared with 52.9% without hemodialysis.

Over the 4-hour hemodialysis period on day 1 for participants with ESRD,the mean±SD cumulative fraction of the 75-mg solriamfetol dose removedwas 20.6%±1.7% (range 19.2% to 24.1%), and the hemodialysis clearancewas 12.4 L/h±1.5 L/h (range 11.3 to 15.9 L/h).

There were no deaths or other serious AEs during this study. A total of4 participants (13%), 1 each in Groups 2 and 3, and 2 in Group 5 (1 withand 1 without hemodialysis), reported 5 treatment-emergent adverseevents (TEAEs; Table 5). This includes single events of nausea, skinabrasion, and headache in 1 participant each, and an increase in alanineaminotransferase (ALT; to 144 IU/L; reference range 8-54 IU/L) andaspartate aminotransferase (AST; to 66 IU/L; reference range 8-40 IU/L)observed 6 days after dosing in 1 participant that led todiscontinuation. All TEAEs were considered by the investigator to bemild, and all but the skin abrasion were considered to be related tostudy drug. All TEAEs resolved, including the increased ALT and AST,which resolved on day 11. No other abnormal laboratory findings wereconsidered clinically meaningful. No clinically significant abnormalfindings were observed in vital sign and ECG measurements.

TABLE 5 Number (%) of Participants with Treatment-Emergent AdverseEvents (TEAEs) End-stage renal disease Normal (Group 5) renal Renalimpairment Group Group function Group 5.1 5.2 Group Group 3 GroupWithout With 1 2 Mod- 4 hemo- hemo- Adverse Normal Mild erate Severedialysis dialysis event (n = 6) (n = 6) (n = 6) (n = 6) (n = 6) (n = 7)Any 0 1 1 0 1 1 TEAE (17%) (17%) (17%) (14%) Nausea 0 0 0 0 1 0 (17%)Skin 0 1 0 0 0 0 abrasion (17%) ALT 0 0 0 0 0 1 increased (14%) AST 0 00 0 0 1 increased (14%) Headache 0 0 1 0 0 0 (17%) ^(a)One participantfrom Group 5 discontinued the study before day 8 due to adverse eventsof mild elevated ALT and AST. ALT, alanine aminotransferase; AST,aspartate aminotransferase; TEAE, treatment-emergent adverse event.

This study showed that renal impairment increases overall exposure tosolriamfetol, with the magnitude of the increase reflecting the level ofimpairment. The incremental decreases in CL/F with worsening renalfunction resulted in corresponding increases in overall solriamfetolexposure that was 53% for mild, 129% for moderate, and 339% for severeimpairment relative to normal renal function. Increasing renalimpairment was also associated with decreasing cumulative percent ofsolriamfetol excreted in urine. The mean percentage of solriamfetol doserecovered in urine as unchanged drug over 48 hours was 85.8%, 80.0%,66.4% and 64.0% (over 72 hours) for subjects with normal renal functionand for subjects with mild, moderate, and severe renal impairment,respectively. Additionally, since there were no substantial changes inV_(d)/F, the decreases in solriamfetol CL/F resulted in increasedt_(1/2) by approximately 1.2-, 1.9-, and 3.9-fold in participants withmild, moderate, and severe renal impairment, respectively, compared withparticipants with normal renal function. In this regard, it should alsobe noted that while C_(max) values were not substantially affected byrenal impairment, the observed increases in t_(1/2) associated withrenal impairment are expected to translate to changes in steady-stateC_(max) that are not fully accounted for by the single-dose regimenevaluated in this clinical study, due to accumulation. AUC and t_(1/2)values increased with increasing levels of renal impairment.Solriamfetol AUC0-inf was higher by approximately 53% (1.53-fold), 129%(2.29-fold), and 339% (4.39-fold) compared with subjects with normalrenal function.

Consistent with the inability of ESRD participants requiringhemodialysis to eliminate solriamfetol via renal excretion, theseparticipants had increased overall exposure to solriamfetol (≥4-fold),longer t_(1/2) values (≥13-fold), and slightly lower C_(max) values(≤19%), relative to participants with normal renal function.Furthermore, ESRD participants had lower solriamfetol C_(max) andAUC_(t) values after undergoing a 4-hour hemodialysis session, with20.6% of the solriamfetol dose removed as unchanged drug. Notably, thesolriamfetol hemodialysis clearance of 12.4 L/h estimated fromsolriamfetol recovered in the dialysate was approximately 30% lower thansolriamfetol renal clearance in participants with normal renal function.

Example 2: Simulations of Solriamfetol Exposure in Patients with RenalImpairment

Methods

A population PK model was developed based on data collected in clinicalstudies. The population PK model provides a unified characterization ofsolriamfetol and of its sources of variability across studies andsub-populations of subjects. The population PK analysis examined theinfluence of potential covariates that have not been evaluated inclinical trials, such as potential differences between narcolepsy andOSA patients, as well as healthy subjects and narcolepsy/OSA patients,and investigated other factors such as age, gender, body weight,race/ethnicity, and formulation effects.

The following thorough evaluation of the source data was performed: (1)Visual inspection of individual plasma concentration-time profiles ofsolriamfetol relative to actual dosing history (e.g., spaghetti plotsfor rich concentration-time profiles, mean profiles); (2) Evaluation ofpotential outliers based on preliminary population PK runs (e.g., usinga one compartment model without covariate); and (3) Review ofdemographic data and baseline characteristics for each study.

The dataset included actual time of observation (sampling and dosing)and main demographic characteristics (covariates) such as age, weight,height, body mass index (BMI), gender, race and markers of renal andliver functions. Extrinsic covariates were also included. The followingmain variables were included in the analysis dataset.

-   -   NMID (unique individual identifier)    -   STUDY (study identifier)    -   SUBJ (subject ID used in the study)    -   DATE (date of the event MM/DD/YYYY)    -   TIME (time of the event HH:MM)    -   DV (plasma concentration of solriamfetol, ng/mL)    -   AMT (actual dose of solriamfetol in mg, calculated based on free        base weight)    -   EVID (event identification for PK observations only: 0=non-below        the limit of quantification [BLQ] PK observation, 1=dose        administration, 2=other-type event [BLQ PK records])    -   MDV (missing data code: 0=non-missing, 1=missing data or        excluded data)    -   BLQ (1=BLQ concentration, 0=non-BLQ concentration or dosing        event)    -   FAST (fasted status during administration: 1=fasted; 0=fed)    -   FORM (formulation: 0=drug substance in capsule; 1=tablet;        2=over-encapsulated tablet)    -   Daily dose (actual dose of solriamfetol in mg, calculated based        on free base weight)    -   DS (disease status: 0=healthy subjects, 1=subjects with        narcolepsy; 2=subjects with OSA)    -   WT (body weight at screening in kg)    -   Age at baseline (age in years)    -   Age as a categorical covariate (i.e., non-elderly vs. elderly        ≥65 years old)    -   Race (White, Black, Asian, Native Hawaiian or other Pacific        Islander, Hispanic, Oriental, other)    -   Ethnicity (1=Hispanic or Latino, 0=non-Hispanic or Latino)    -   Gender (0=female, 1=male)    -   TAD (time after previous dose in h)    -   VISIT (visit number)    -   NTIME (nominal time after the dose in hours)    -   CRCL at baseline (creatinine clearance in mL/min calculated by        Cockcroft-Gault formula) (Cockcroft D W, Gault M H: Prediction        of creatinine clearance from serum creatinine. Nephron 1976; 16:        31-41)    -   eGFR at baseline    -   Renal impairment status based on Food and Drug Administration        (FDA) guidance 10:        -   Normal: eGFR≥90 mL/min/1.73 m²        -   Mild: eGFR 60-89 mL/min/1.73 m² (i.e., ≥60 to <90)        -   Moderate: eGFR 30-59 mL/min/1.73 m² (i.e., ≥30 to <60)        -   Severe: eGFR 15-29 mL/min/1.73 m² (i.e., ≥15 to <30) and not            on hemodialysis        -   End-stage renal disease (ESRD): eGFR<15 mL/min/1.73 m² and            not on hemodialysis or patients on hemodialysis    -   HT (height in m)    -   BMI at baseline (body mass index in kg/m2)    -   BSA at baseline (body surface area, calculated by Dubois and        Dubois formula) (DuBois D; DuBois E F: A formula to estimate the        approximate surface area if height and weight be known. Arch Int        Med 1916 17:863-71)    -   ALT at baseline (alanine aminotransferase in U/L)    -   AST at baseline (aspartate aminotransferase in U/L)    -   ALB at baseline (albumin in g/L)    -   Bioanalytical method (High performance liquid chromatography        [HPLC] or Liquid chromatography-tandem mass spectrometry        [LC-MS/MS]).        Base Population PK Model Buildup

In a first step, compartmental PK models without covariates wereevaluated to assess the PK of solriamfetol. One and two-compartmentmodels with linear disposition were tested to assess theconcentration-time profiles of solriamfetol.

Model Buildup

The population PK model included the following.

1. A structural component describing the relationships between plasmaconcentration and time using the following equation:Cp _(ij) =C(D _(i) ,t _(j),θ_(i))·(1+ε_(p,ij))+ε_(α,ij)θ_(i)=(θ_(i1), . . . ,θ_(ip))wherein Cp_(ij) is the concentration at the j^(th) collection time t_(j)for subject i, Di represents dosing history for subject i, ϑ_(i) is thevector of p different PK parameters for subject i, and ε_(p,ij) andε_(α,ij) are the proportional and additive random residual error terms,respectively, associated with jth concentration for subject i. ε_(p) andε_(a) are normally distributed with mean 0 and variances σ_(p) ² andσ_(a) ², respectively.

2. A variance component characterizing between-subject variability (BSV)and, if required, inter-occasion variability (IOV) in model parameters.θ_(ink)=(θ_(TV,n) e ^((η) ^(in) ^(+ψ) ^(ink) ⁾)(η₁, . . . ,η_(p))=MVN(0,Ω)ψ_(n,k) =N(0,Φ_(n))where θ_(ink) is the value of the n^(th) PK parameter of the ithindividual on the kth occasion, θ_(TV,n) is the typical value of the nthPK parameter in the population, η_(in) is the random inter-individualdeviation from the typical value θ_(TV,n) for subject i, and ψ_(ink) isthe random inter-occasion subject deviation from the value of the nthparameter for subject i on occasion k. Inter-individual random effects(η₁, . . . , η_(m)), also known as ETAs, are multivariate normallydistributed with mean 0 and estimated variance ω_(n) ² included in thevariance-covariance OMEGA (Ω) matrix. Inter-occasion random effects forthe nth parameter ψ_(nk) are normally distributed with mean 0 andvariance Φ_(n), with all ψ_(n1), . . . , ψ_(nm) sharing the samevariance, where m is the number of occasions.

The evaluation of the BSV/IOV models included possible addition of BSVterms (ETAs) to the model parameters, evaluation of the most appropriateform of the ETAs, and evaluation of pairwise plots of the ETAs for anycorrelations. Covariance between ETA terms was estimated in the modelwhere correlations between ETAs were deemed probable based on thesediagnostic plots. Models with shared ETA were also considered.

3. Error models describing residual unexplained variability in the formof additive, proportional or additive and proportional models:y _(ij) =ŷ _(ij)*(1+ε_(1ij))+ε_(2ij)where y_(ij) and ŷ_(ij) represent the jth observed and predicted plasmadrug concentration for the ith participant and ε is the random residualvariability. Each ε (ε₁ and ε₂) is normally distributed with mean 0 andvariance σ². An allometric function accounting for body weight effect onclearance (CL/F) and volume of distribution (V/F) was included in themodel. In addition, the effect of creatinine clearance was added on CL/Fsince the drug was previously demonstrated to undergo important renalexcretion.Model Evaluation

Consistent with the FDA/EMA Guidance for Industry, evaluation of themodels was based on the following.

-   -   Standard model diagnostics and standard statistical criteria of        goodness-of-fit criteria such as the log-likelihood difference        between alternative models (e.g., a decrease in the objective        function value [OFV])    -   Successful model convergence    -   Examining pertinent graphical representations of        goodness-of-fit:        -   Observed data versus population predicted data (DV vs. PRED)            and individual predicted data (DV vs. IPRED) with a line of            unity and a trend line, on linear and log scales        -   Observed Data versus time after the 1st dose and after the            previous dose (DV vs. time and DV vs. TAD) with trend lines            of DV and PRED, on linear and log scales        -   Conditional weighted residuals versus predicted data (CWRES            vs. PRED) with zero line and a trend line        -   Conditional weighted residuals versus time after the 1st            dose and previous dose [CWRES vs. time and CWRES vs. TAD]            with zero line and a trend line        -   Quantile-quantile plot of CWRES (QQ plot)    -   Estimating shrinkage of the empirical Bayesian estimates (EBEs)        of the model parameters was evaluated for diagnostic purpose.        The shrinkage magnitude for a structural parameter θ        (η-shrinkage) was calculated as follow:

${sh}_{\theta} = {1 - \frac{S\;{D\left( \eta_{{EBE},P} \right)}}{\omega_{\theta}}}$where SD(η_(EBE,P)) is the standard deviation of the individual EBEs forparameter P, ω_(P) is the model estimate of the standard deviationassociated with parameter P. If no shrinkage in parameter P is present,the ratio between SD(η_(EBE,P)) and ω_(P) is unity, and shP becomeszero. Shrinkage reflects the degree of information available in the datato estimate the random effects independently, where a shrinkage of 100%reflects a case where there is no information at all on the randomeffect and all individual parameters revert back to the populationestimate. Covariate effects may be interpreted with caution for PKparameters associated with high shrinkage (e.g., >30%), as theindividual random effect estimates are expected to shrink towards zero.Incorporation of Assay Conversion Factor

All plasma samples were assayed using an LC-MS/MS or an HPLC method.Exploratory analyses were performed to investigate potential differencesin concentrations determined using the two different methods, and wereused to guide further steps in model development, and whether or not aneffect of assay was to be included as part of the base population PKmodel or the residual error model. As a consequence of the observeddifferences in concentrations due to use of the two different assaymethodologies, an assay conversion factor (CF) was incorporated into themodel to scale solriamfetol concentrations from HPLC assay to LC-MS/MSas per the following linear and nonlinear models:Linear CF: C _(LC-MS/MS)=(C _(HPLC))×CFNonlinear CF: C _(LC-MS/MS)=(C _(HPLC))^(CF)

In addition, different error models were considered for each assay. TheCF was tested in the additive and proportional components of the errormodels. The selection of the final CF model was based on quality-of-fitusing standard graphical representations of goodness-of-fit, includingthe diagnostic plots.

Sources of Variability and Covariate Analysis

The relationships between PK parameters and covariates were exploredgraphically to identify the covariates likely to affect the PK ofsolriamfetol. Scatter plots of the relationships between the randomeffect of PK parameters and continuous variables included LOESS lines,Pearson correlation coefficients, and the corresponding p-value for eachrelationship. Box plots were used to describe the relationship forcategorical covariates. The investigated intrinsic factors included thefollowing.

-   -   Age at baseline (as a continuous covariate in years and/or        categorical covariate [i.e., non-elderly (18-64) vs. elderly        (≥65 years old)]). Covariate was tested on CL/F, V/F and Ka.    -   Gender. Covariate was tested on CL/F and V/F.    -   Measures of body size at baseline (i.e., body weight): Included        in the base model on CL/F and V/F.    -   Ethnic origin/Race. Covariates were tested on CL/F and V/F.    -   Markers of renal function at baseline (based on creatinine        clearance): Included in the base model on CL/F.    -   Markers of liver function at baseline (ALB, ALT and AST).        Covariates were tested on CL/F and V/F.

The investigated extrinsic factors included:

-   -   Nominal dose levels of JZP-110. Covariate was tested on CL/F,        V/F and Ka.    -   Formulation (Over-encapsulated Tablet vs. Tablet vs. drug        substance in Capsule). Covariate was tested on CL/F, V/F and Ka.    -   Fasted status (i.e., fed vs. fasted). Covariate was tested on        Tlag and Ka.    -   Disease status. Covariate was tested on CL/F and V/F.        -   Healthy subjects        -   Subjects with narcolepsy        -   Subjects with OSA

In the next step, the most relevant covariates were formally evaluatedwithin the population PK model using a stepwise forward additiveapproach using a p-value of 0.01 (ΔOFV=6.63, for one degree of freedom[df]) and a backward elimination approach using a p-value of 0.001(ΔOFV=10.83, for one df).

In addition, a nonparametric bootstrap resampling analysis wasperformed. The bootstrap technique involves repeatedly drawing randomsamples from the original data, with replacement. The bootstrap was usedto reduce the model by removing covariates for which the 95% predictioninterval (PI) included the null value relative to the referencepopulation. Statistically significant covariates identified during thecovariate analysis were displayed graphically in a forest plot. See,Menon-Andersen D, Yu B, Madabushi R, Bhattaram V, Hao W, Uppoor R S,Mehta M, Lesko L, Temple R, Stockbridge N, Laughren T, Gobburu J V.Essential pharmacokinetic information for drug dosage decisions: aconcise visual presentation in the drug label. Clin Pharmacol Ther. 2011September; 90(3):471-4.

Final Model

The final population PK model was evaluated using visual predictivecheck (VPC). Based on the estimates of the final model,concentration-time profiles were simulated using 1000 replicates.Observed and simulated data were separated into distinct bins. Withineach bin, a 95% confidence interval of the 5th, 50^(th) and 95thprediction intervals was obtained by simulation. The confidenceintervals give an indication of the uncertainty of the predictions. The5th, 50th and 95th percentiles of observed concentrations were comparedto the 95% confidence intervals.

The final population PK model was used to simulate richconcentration-time profiles of solriamfetol in adult subjects with renalimpairment (mild, moderate, severe, and ESRD) and in pediatric patientsfollowing administration of different dosing regimens.

The final population PK model was used to perform simulations in 10000narcolepsy/OSA patients for each dose level of solriamfetol tabletformulation (37.5, 75, 150, and 300 mg), and exposure parameters(AUCtau, C max, C min, C14h and t1/2) were derived.

Descriptive statistics of exposure parameters for each dose level andaccording to each renal impairment category are presented in Tables6-10. Boxplots of exposure parameters for each dose level and accordingto each renal impairment category are presented in FIGS. 3-7. Simulatedconcentration-time profiles for each dose level and according to eachrenal impairment category are presented in Table 8.

TABLE 6 Simulations to Support Dosing in Sub-Populations - AdultPatients (Narcolepsy/OSA, tablet, fasting conditions) with Normal RenalFunction Dose (mg) - Solriamfetol 37.5 75 150 300 Parameters (n = 10000)(n = 10000) (n = 10000) (n = 10000) AUC_(tau) (ng · h/mL) Mean (CV %)1931 (34.4%) 4139 (34.4%) 8874 (34.4%) 19024 (34.4%) Median 1822 39068382 17952 [Min, Max] [471, 76711] [1010, 16473] [2165, 35375] [4641,759681] Geom. Mean 1825 (34.6%) 3912 (34.6%) 8387 (34.6%) 17980 (34.6%)(Geom. CV %) C_(max) (ng/mL) Mean (CV %) 202 (24.5%) 410 (24.6%) 835(24.8%) 1702 (25.0%) Median 197 399 811 1654 [Min, Max] [79.1, 4941][160, 1004] [323, 2086] [656, 4370] Geom. Mean 196 (24.5%) 398 (24.6%)810 (24.8%) 1651 (25.0%) (Geom. CV %) C_(min) (ng/mL) Mean (CV %) 19.6(78.9%) 46.7 (75.0%) 110 (71.5%) 259 (68.4%) Median 15.8 38.3 92.2 219[Min, Max] [0.0290, 194] [0.104, 432] [0.362, 961] [1.21, 2132] Geom.Mean 14.3 (108%) 35.0 (99.2%) 84.9 (92.1%) 204 (85.9%) (Geom. CV %)C_(14h) (ng/mL) Mean (CV %) 53.6 (50.3%) 120 (48.5%) 268 (46.9%)595(45.5%) Median [Min, 49.1 111 248 552 Max] [1.21, 296] [3.39, 642][9.32, 1390] [25.1, 3007] Geom. Mean 47.1 (57.7%) 106 (54.7%) 240(52.2%) 536 (50.0%) (Geom. CV %) Half-life (h) Mean (CV %) 6.35 (30.7%)6.81 (30.7%) 7.30 (30.7%) 7.82 (30.7%) Median [Min, 6.08 6.52 6.99 7.50Max] [1.71, 21.4] [1.83, 22.9] [1.96, 24.5] [2.10, 26.3] Geom. Mean 6.08(30.5%) 6.51 (30.4%) 6.98 (30.4%) 7.48 (30.5%) (Geom. CV %) AUC_(tau):Area under the concentration-time curve at steady state; C_(14h):concentration at 14 h post-dose at steady state; C_(max): maximumconcentration at steady state; C_(min): concentration at 24 h post-doseat steady state; CV %: coefficient of variation; Min: minimum; Max:maximum; n: number of subjects.

TABLE 7 Simulations to Support Dosing in Sub-Populations - AdultPatients (Narcolepsy/OSA, tablet, fasting conditions) with Mild RenalImpairment Reference (Adult, Dose = 150 mg, Normal Dose Renal 37.5 mg 75mg 150 mg 300 mg Parameters Function) (n = 10000) (n = 10000) (n =10000) (n = 10000) AUC_(tau) (ng · h/mL) Mean (CV %) 8874 (34.4%) 26245626 12059 25853 (34.3%) (34.2%) (34.2%) (34.2%) Median 8382 2479 532011395 24428 [Min, Max] [2165, [721, 9598] [1548, 20619] [3321, 44294][7124, 95152] 35375] Geom. Mean 8387(34.6%) 2482 5321 11407 24453 (Geom.CV %) (34.4%) (34.3%) (34.3%) (34.3%) C_(max) (ng/mL) Mean (CV %) 835(24.8%) 225 (24.8%) 461 946 1945 (25.1%) (25.3%) (25.6%) Median 811 219448 919 1890 [Min, Max] [323, 2086] [82.4, 550] [167, 1158] [338, 2444][686, 5171] Geom. Mean 810 (24.8%) 218 (24.8%) 447 917 1884 (Geom. CV %)(25.6%) (25.3%) (25.1%) C_(min) (ng/mL) Mean (CV %) 110 (71.5%) 39.8(64.5%) 91.8 211 482 (57.4%) (61.9%) (59.5%) Median 92.2 34.3 80.1 186428 [Min, Max] [0.362, 9611] [0.677, 289] [2.06, 636] [6.09, 1396][17.5, 3062] Geom. Mean 84.9 (92.1%) 32.2 (77.9%) 75.7 177 409 (65.8%)(Geom. CV %) (73.3%) (69.3%) C_(14h) (ng/mL) Mean (CV %) 268 (46.9%)84.9(43.8%) 187 411 902 (40.8%) (42.6%) (41.6%) Median 248 [9.32, 79.1[8.46, 175 [21.3, 384 [52.6, 845 [128, [Min, Max] 1390] 385] 830] 1791]3861] Geom. Mean 240 (52.2%) 77.2 171 378 831 (42.9%) (Geom. CV %)(47.2%) (45.6%) (44.1%) Half-life (h) Mean (CV %) 7.30 (30.7%) 8.67(30.8%) 9.29 9.96 10.7 (30.7%) (30.7%) (30.7%) Median 6.99 8.26 8.859.48 10.2 [Min, Max] [1.96, 24.5] [2.69, 26.1] [2.88, 28.0] [3.09, 30.0][3.31, 32.2] Geom. Mean 6.98 (30.4%) 8.29 (30.4%) 8.89 9.53 10.2 (Geom.CV %) (30.4%) (30.4%) (30.4%) AUC_(tau): Area under theconcentration-time curve at steady state; C_(14h): concentration at 14 hpost-dose at steady state; C_(max): maximum concentration at steadystate; C_(min): concentration at 24 h post-dose at steady state; CV %:coefficient of variation; Min: minimum; Max: maximum; n: number ofsubjects.

TABLE 8 Simulations to Support Dosing in Sub-Populations - AdultPatients (Narcolepsy/OSA, tablet, fasting conditions) with ModerateRenal Impairment Reference (Adult, Dose = 150 mg, Normal Dose Renal 37.5mg 75 mg 150 mg 300 mg Parameters Function) (n = 10000) (n = 10000) (n =10000) (n = 10000) AUC_(tau) (ng · h/mL) Mean (CV %) 8874 (34.4%) 3743(36.6%) 8024 (36.6%) 17201 (36.5%) 36875 (36.5%) Median 8382 3518 753916157 34617 [Min, Max] [2165, [777, 14484] [1666, [3570, 67577] [7652,145970] 35375] 31285] Geom. Mean 8387 (34.6%) 3517 (36.4%) 7540 (36.4%)16164 34651 (Geom. CV %) (36.3%) (36.3%) C_(max) (ng/mL) Mean (CV %) 835(24.8%) 266 (26.8%) 550 1139 2366 (28.0%) (27.2%) (27.6%) Median [Min,811 [323, 255 [87.6, 527 [179, 1093 [365, 2267 [748, Max] 2086] 810]1712] 3624] 7684] Geom. Mean 810 (24.8%) 257 (26.4%) 531 1099 2280(27.6%) (Geom. CV %) (26.8%) (27.2%) C_(min) (ng/mL) Mean (CV %) 110(71.5%) 78.3 (57.9%) 177 397 (54.5%) 888 (53.0%) (56.1%) Median [Min,92.2 [0.362, 69.6 [1.00, 158 [2.86, 356 [7.96, 801 [21.7, Max] 961] 434]961] 2126] 4695] Geom. Mean 84.9 (92.1%) 66.4 (65.6%) 151 343 (60.2%)774 (58.0%) (Geom. CV %) (62.8%) C_(14h) (ng/mL) Mean (CV %) 268 (46.9%)135 (42.4%) 293 638 (41.1%) 1385 (40.5%) (41.7%) Median [Min, 248 [9.32,125 [9.10, 273 [22.4, 594 [54.3, 1294 [130, Max] 1390] 573] 1243] 2699]5855] Geom. Mean 240 (52.2%) 123 (44.1%) 270 588 (42.3%) 1281 (41.5%)(Geom. CV %) (43.1%) Half-life (h) Mean (CV%) 7.30 (30.7%) 12.4 (32.6%)13.2 14.2 (32.5%) 15.2 (32.5%) (32.5%) Median [Min, 6.99 [1.96, 11.8[3.14, 12.6 [3.37, 13.5 [3.61, 14.5 [3.87, Max] 24.5] 40.3] 43.2] 46.3]49.7] Geom. Mean 6.98 (30.4%) 11.8 (32.4%) 12.6 13.5 (32.4%) 14.5(32.4%) (Geom. CV %) (32.4%) AUC_(tau): Area under theconcentration-time curve at steady state; C_(14h): concentration at 14 hpost-dose at steady state; C_(max): maximum concentration at steadystate; C_(min): concentration at 24 h post-dose at steady state; CV %:coefficient of variation; Min: minimum; Max: maximum; n: number ofsubjects.

TABLE 9 Simulations to Support Dosing in Sub-Populations - AdultPatients (Narcolepsy/OSA, tablet, fasting conditions) with Severe RenalImpairment Reference (Adult, Dose = 150 mg, Normal Dose Renal 37.5 mg 75mg 150 mg 300 mg Parameters Function) (n = 10000) (n = 10000) (n =10000) (n = 10000) AUC_(tau) (ng · h/mL) Mean (CV %) 8874 (34.4%) 596712790 (36.8%) 27416 (36.8%) 58772 (36.8%) (36.9%) Median 8382 5608 1202625790 55249 [Min, Max] [2165, 35375] [1448, 20711] [3129, 44391] [6762,95179] [14323, 205161] Geom. Mean 8387 (34.6%) 5602 12009 (36.6%) 25744(36.6%) 55188 (36.5%) (Geom. CV %) (36.6%) C_(max) (ng/mL) Mean (CV %)835 (24.8%) 353 (29.3%) 738 (29.7%) 1546 (30.1%) 3243 (30.5%) Median[Min, 811 338 705 1475 3089 Max] [323, 2086] [116, 1014] [240, 2150][496, 4561] [1029, 9681] Geom. Mean 810 (24.8%) 339 (28.8%) 708 (29.2%)1482 (29.6%) 3105 (30.0%) (Geom. CV %) C_(min) (ng/mL) Mean (CV %) 110(71.5%) 163 (49.6%) 360 (48.6%) 794 (47.6%) 1748 (46.8%) Median 92.2 149330 728 1608 [Min, Max] [0.362, 961] [15.8, 737] [37.9, 1606] [90.0,3498] [212, 7613] Geom. Mean 84.9 (92.1%) 145 (52.5%) 322 (51.0%) 713(49.7%) 1576 (48.6%) (Geom. CV %) C_(14h) (ng/mL) Mean (CV %) 268(46.9%) 231 (39.7%) 498 (39.4%) 1076 (39.0%) 2322 (38.8%) Median 248 216468 1010 2178 [Min, Max] [9.32, 1390] [45.4, 841] [101, 1816] [226,3919] [498, 8460] Geom. Mean 240 (52.2%) 214 464 (39.7%) 1002 (39.3%)2164 (38.9%) (Geom. CV %) (40.1%) Half-life (h) Mean (CV %) 7.30 (30.7%)19.7 21.1 (33.0%) 22.6 (33.0%) 24.2 (33.0%) (33.1%) Median 6.99 18.720.0 21.5 23.0 [Min, Max] [1.96, 24.5] [5.21, 70.6] [5.57, 75.7] [5.96,81.1] [6.37, 86.9] Geom. Mean 6.98 (30.4%) 18.7 20.0 (32.9%) 21.5 23.0(32.8%) (Geom. CV %) (32.9%) (32.8%) AUC_(tau): Area under theconcentration-time curve at steady state; C_(14h): concentration at 14 hpost-dose at steady state; C_(max): maximum concentration at steadystate; C_(min): concentration at 24 h post-dose at steady state; CV %:coefficient of variation; Min: minimum; Max: maximum; n: number ofsubjects.

TABLE 10 Simulations to Support Dosing in Sub-Populations - AdultPatients (Narcolepsy/OSA, tablet, fasting conditions) with ESRDReference (Adult, Dose = 150 mg , Normal Dose Renal 37.5 mg 75 mg 150 mg300 mg Parameters Function) (n = 10000) (n = 10000) (n = 10000) (n =10000) AUC_(tau) (ng · h/mL) Mean (CV %) 8874 25371 (42.5%) 54399(42.6%) 116645 250132 (42.7%) (34.4%) (42.7%) Median 8382 23288 49948107070 229500 [Min, Max] [2165, 35375] [5989, 136885] [12737, 292530][27087, 625152] [57605, 1335983] Geom. Mean 8387 23394 (41.7%) 50152(41.8%) 107514 (41.8%) 230486 (41.9%) (Geom. CV %) (34.6%) C_(max)(ng/mL) Mean (CV %) 835 1153 (39.8%) 2456 (40.0%) 5234 (40.3%) 11162(40.5%) (24.8%) Median [Min, 811 1065 2267 4827 10282 Max] [323, 2086][290, 5893] [617, 12563] [1310, 26789] [2786, 57133] Geom. Mean 810 1074(38.6%) 2286 (38.9%) 4868 (39.1%) 10373 (39.4%) (Geom. (24.8%) CV %)C_(min) (ng/m L) Mean (CV %) 110 961 (45.7%) 2075 (45.6%) 4476 (45.4%)9655 (45.3%) (71.5%) Median [Min, 92.2 876 1891 4084 8816 Max] [0.362,961] [183, 5509] [398, 11801] [862, 25275] [1866, 54124] Geom. Mean 84.9875 (45.6%) 1889 (45.3%) 4079 (45.1%) 8803 (45.0%) (Geom. (92.1%) CV %)C_(14h) (ng/mL) Mean (CV %) 268 1045 (43.0%) 2243 (43.0%) 4814 (43.0%)10333 (43.1%) (46.9%) Median 248 958 2056 4413 9473 [Min, Max] [9.32,1390] [236, 5689] [505, 12161] [1079, 25995] [2304, 55566] Geom. Mean240 962 (42.3%) 2064 (42.2%) 4430 (42.3%) 9509 (42.3%) (Geom. (52.2%) CV%) Half-life (h) Mean (CV %) 7.30 83.6 (38.1%) 89.7 (38.2%) 96.1 (38.3%)103 (38.4%) (30.7%) Median 6.99 77.9 83.4 89.6 95.9 [Min, Max] [1.96,24.5] [20.8, 337] [22.3, 363] [23.9, 392] [25.5, 422] Geom. Mean 6.9878.1 (38.1%) 83.7 (38.2%) 89.8 (38.2%) 96.2 (38.3%) (Geom. (30.4%) CV %)AUC_(tau): Area under the concentration-time curve at steady state;C_(14h): concentration at 14 h post-dose at steady state; C_(max):maximum concentration at steady state; C_(min): concentration at 24 hpost-dose at steady state CV %: coefficient of variation; Min: minimum;Max: maximum; n: number of subjects.

Ratios were generated to facilitate the comparison across populations ofpatients with renal impairment in order to optimally match the exposureof the reference dose in adult patients with normal renal function(i.e., 150 mg). Ratios of AUC_(tau), C_(mas), C_(min), C_(14h) andt_(1/2) are presented in Table 11.

TABLE 11 Ratio of Mean Steady State PK Parameters of Solriamfetol inPatients with Renal Impairment (at different doses) Relative to Patientswith Normal Renal Function (at 150 mg dose) Ratio Relative to TypicalPatient with Dose Normal Renal Function Sub-Population (mg) AUC_(tau)C_(max) C_(14h) C_(min) _(t1/2) Mild Renal 300 2.91 2.33 3.37 4.38 1.47Impairment 150 1.36 1.13 1.53 1.92 1.36 75 0.63 0.55 0.70 0.83 1.27 37.50.30 0.27 0.32 0.36 1.19 Moderate Renal 300 4.16 2.83 5.17 8.07 2.08Impairment 150 1.94 1.36 2.38 3.61 1.95 75 0.90 0.66 1.09 1.61 1.81 37.50.42 0.32 0.50 0.71 1.70 Severe Renal 300 6.62 3.88 8.66 15.89 3.32Impairment 150 3.09 1.85 4.01 7.22 3.10 75 1.44 0.88 1.86 3.27 2.89 37.50.67 0.42 0.86 1.48 2.70 ESRD 300 28.19 13.37 36.56 87.77 14.11 150 13.16.27 18.0 40.7 13.2 75 6.13 2.94 8.37 18.9 12.3 37.5 2.86 1.38 3.90 8.7411.5 AUC_(tau): Area under the concentration-time curve at steady state;C_(max): maximum concentration at steady state; C_(14h): concentrationat 14 h post-dose at steady state; C_(min): concentration at 24 hpost-dose at steady state; t_(1/2): elimination half-life.

Based on the inventor's analyses of solriamfetol's pharmacokinetics andsafety profile together with population PK simulations, it wasdiscovered that, in patients with mild renal impairment, an equivalentdose used in patients with normal renal function was associated withcomparable exposures. A 150 mg dose in patients with mild renalimpairment is associated with AUC_(tau) and C_(max) values 36% and 13%higher than those observed in patients with normal renal function forthe same dose. Typical C_(14h) and C_(min) values in a patient with mildrenal impairment are expected to be approximately 1.5- and 2-fold higherthan that observed in patients with normal renal function due to thelonger t_(1/2). Therefore, no dosage adjustments should be needed inpatients with mild renal impairment and this subgroup of renallyimpaired patients can be safety administered at an initial daily doseequivalent to 75 mg of solriamfetol and escalating to a maximum dailydose equivalent to 150 mg of solriamfetol after at least 3 days, basedon solriamfetol's elimination half-life.

In patients with moderate renal impairment, one-half of the dose used inpatients with normal renal function was associated with comparableexposures. A 75 mg dose in patients with moderate renal impairment isassociated with AUC_(tau) and C_(max) values 10% and 34% lower thanthose observed in patients with normal renal function at a 150 mg dose.Typical C_(14h) and C_(min) values in a patient with moderate renalimpairment is expected to be approximately 9% and 61% higher than thatobserved in patients with normal renal function due to the longert_(1/2). Therefore, dosing adjustments are warranted in patients withmoderate renal impairment. The appropriate dose escalation regimen forthis subgroup of renally impaired patients was determined by the presentinventor to be an initial daily dose equivalent to 37.5 mg solriamfetoland escalating to a maximum daily dose equivalent to 75 mg solriamfetolafter at least five days to at least seven days, based on solriamfetol'selimination half-life.

In patients with severe renal impairment, one-quarter of the dose usedin patients with normal renal function was associated with comparableexposures. A 75 mg dose in patients with severe renal impairment wasassociated with AUC_(tau) and C_(max) values 44% higher and 12% lowerthan those in patients with normal renal function at a 150 mg dose.Typical C_(14h) and C_(min) following a 75 mg dose in patients withsevere renal impairment is expected to be approximately 1.9- and 3-foldhigher than that in patients with normal renal function. Therefore, itwas determined that a 75 mg dose would not be appropriate for patientswith severe renal impairment. Therefore, dosing adjustment is warrantedin patients with severe renal impairment. A 37.5 mg dose in patientswith severe renal impairment was associated with AUC_(tau) and C_(max)values 33% lower and 58% lower than those in patients with normal renalfunction at a 150 mg dose. Typical C_(14h) and C_(min) values followinga 37.5 mg dose in a patient with severe renal impairment are expected tobe 14% lower and 48% higher than that in patients with normal renalfunction. Therefore, dosing adjustments is warranted in patients withsevere renal impairment. The appropriate dose escalation regimen forthis subgroup of renally impaired patients was determined by the presentinventor to be a daily maximum dose equivalent to 37.5 mg ofsolriamfetol.

Based on the substantial increase in solriamfetol exposure in patientswith ESRD, use of solriamfetol in this subpopulation should be avoided.

The foregoing is illustrative of the present invention, and is not to beconstrued as limiting thereof. The invention is defined by the followingclaims, with equivalents of the claims to be included therein. Allpublications, patent applications, patents, patent publications, and anyother references cited herein are incorporated by reference in theirentireties for the teachings relevant to the sentence and/or paragraphin which the reference is presented.

What is claimed is:
 1. A method of treating excessive daytime sleepinessassociated with obstructive sleep apnea in a renally impaired subject inneed thereof according to a dose escalation regimen, said methodcomprising providing to the subject a first oral daily dose equivalentto 37.5 mg [R]-2-amino-3-phenylpropylcarbamate (APC) from day one to dayn₁ of the dose escalation regimen; and providing to the subject a secondoral daily dose equivalent to 75 mg APC starting on day n₂ of the doseescalation regimen, wherein n₁ is an integer equal to or greater than 5and n₂ is equal to the sum of n₁+1, wherein the renally impaired subjectis not provided a daily dose exceeding a dose equivalent to 75 mg APC,and wherein the renally impaired subject has an estimated glomerularfiltration rate (eGFR) of about 30 mL/min/1.73 m² to about 59mL/min/1.73 m².
 2. The method of claim 1, wherein the subject isprovided the first oral daily dose in the form of about 44.7 ma APC-HCl.3. The method of claim 1, wherein the subject is provided the secondoral daily dose in the form of about 89.3 mg APC-HCl.
 4. The method ofclaim 1, wherein the subject is provided a first oral daily dose in theform of about 44.7 mg APC-HCl and a second oral daily dose in the formof about 89.3 mg APC-HCl.
 5. The method of claim 1, wherein the firstoral daily dose and second oral daily dose are each administered uponthe subject's awakening.
 6. The method of claim 1, wherein the firstoral daily dose and second oral daily dose are each administered morethan nine hours in advance of the subject's bedtime.
 7. The method ofclaim 1, wherein the subject is a human.
 8. The method of claim 1,wherein the eGFR is determined using the Modification in Diet in RenalDisease equation.
 9. The method of claim 1, wherein n₁ is an integerequal to or greater than 7.